WIP implement full history of account balance snapshot

Runaway redistribution

See merge request cicnet/erc20-demurrage-token!10

.gitignore

@@ -6,3 +6,5 @@ __pycache__
 gmon.out
 solidity/*.json
 solidity/*.bin
+.venv
+venv

.gitlab-ci.yml

@@ -0,0 +1,36 @@
+# To contribute improvements to CI/CD templates, please follow the Development guide at:
+# https://docs.gitlab.com/ee/development/cicd/templates.html
+# This specific template is located at:
+# https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/ci/templates/Python.gitlab-ci.yml
+
+# Official language image. Look for the different tagged releases at:
+# https://hub.docker.com/r/library/python/tags/
+image: python:3.8
+
+# Change pip's cache directory to be inside the project directory since we can
+# only cache local items.
+variables:
+  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
+
+# Pip's cache doesn't store the python packages
+# https://pip.pypa.io/en/stable/reference/pip_install/#caching
+#
+# If you want to also cache the installed packages, you have to install
+# them in a virtualenv and cache it as well.
+cache:
+  paths:
+    - .cache/pip
+    - venv/
+
+before_script:
+  - cd ./python
+  - python --version  # For debugging
+  - pip install virtualenv
+  - virtualenv venv
+  - source venv/bin/activate
+
+test:
+  script:
+    - pip install -r requirements.txt -r test_requirements.txt --extra-index-url https://pip.grassrootseconomics.net
+    - bash run_tests.sh 
+

CAVEAT

@@ -0,0 +1,5 @@
+The contract is intended for slow rates of decay (e.g. 2% per month). Very high levels of decay (2% per minute) will lead to overflows, and will need a more flexible implementation to support it.
+
+The contract is written with frequent usage in mind. If used for tokens with low usage freqency (e.g. several days idle), it is recommended to run a continuous process triggering the changePeriod() contract call, to reduce the amount of exponential calculation the application of demurrage will trigger.
+
+When changing the period, the supply for the consecutive period will be taken at the time of code execution, and thus not necessarily at the time when the redistribution period threshold was crossed. 

ROADMAP

@@ -0,0 +1,8 @@
+- 0.1.3
+	* Snapshot supply for crossed redistribution thresholds before minting new tokens.
+- 0.1.4
+	* Implement natural logarithm 
+- 0.1.5
+	* Port changes from SingleNocap to SingleCap
+- 0.2.0
+	* Make decay resolutions configurable, to support high levels of decay.

VERSION

@@ -0,0 +1 @@
+0.1.2

python/CHANGELOG

@@ -1,4 +1,20 @@
-- 0.0.2-pending
+- 0.2.0
+	* Add token burn function
+	* Fix gas leak when calculating decay on period change
+	* Remove all but SingleNocap contract in make install
+	* Make approve explicitly set value
+	* Add increaseAllowance and decreaseAllowance methods
+- 0.1.1
+	* Settable demurrage steps for apply demurrage cli tool
+- 0.1.0
+	* Dependency upgrades
+- 0.0.11
+	* Apply demurrage cli tool
+- 0.0.10
+	* Settable sink address
+- 0.0.9
+	* Correct redistribution amount for SingleNocap contract
+- 0.0.2
 	* Move to chainlib-eth
-- 0.0.1-unreleased
+- 0.0.1
 	* Interface for redistributed and non-redistributed, with or without cap

python/MANIFEST.in

@@ -1 +1 @@
-include erc20_demurrage_token/data/*
+include erc20_demurrage_token/data/* erc20_demurrage_token/data/config/*.ini *requirements.txt

python/erc20_demurrage_token/demurrage.py

@@ -0,0 +1,67 @@
+# standard imports
+import logging
+import datetime
+import math
+
+# eternal imports
+from chainlib.eth.constant import ZERO_ADDRESS
+
+# local imports
+from .token import DemurrageToken
+
+logg = logging.getLogger(__name__)
+
+
+class DemurrageCalculator:
+
+    def __init__(self, interest_f_minute):
+
+        self.r_min = interest_f_minute
+        self.r_hour = 1 - ((1 -self.r_min) ** 60)
+        self.r_day = 1 - ((1 -self.r_hour) ** 24)
+        #self.r_week = interest_f_day ** 7
+        logg.info('demurrage calculator set with min {:.32f} hour {:.32f} day {:.32f}'.format(self.r_min, self.r_hour, self.r_day))
+
+
+    def amount_since(self, amount, timestamp):
+        delta = datetime.datetime.utcnow() - datetime.datetime.fromtimestamp(timestamp)
+        adjusted_amount = amount * ((1 - self.r_day) ** (delta.days))
+        logg.debug('adjusted for {} days {} -> {}'.format(delta.days, amount, adjusted_amount))
+
+        remainder = delta.seconds
+        remainder_hours = math.floor(remainder / (60 * 60))
+        adjusted_delta = adjusted_amount * ((1 - self.r_hour) ** remainder_hours)
+        adjusted_amount -= (adjusted_amount - adjusted_delta)
+        logg.debug('adjusted for {} hours {} -> {} delta {}'.format(remainder_hours, amount, adjusted_amount, adjusted_delta))
+
+        remainder -= (remainder_hours * (60 * 60))
+        remainder_minutes = math.floor(remainder / 60)
+        adjusted_delta = adjusted_amount * ((1 - self.r_min) ** remainder_minutes)
+        adjusted_amount -= (adjusted_amount - adjusted_delta)
+        logg.debug('adjusted for {} minutes {} -> {} delta {}'.format(remainder_minutes, amount, adjusted_amount, adjusted_delta))
+
+        return adjusted_amount
+
+    
+    def amount_since_slow(self, amount, timestamp):
+        delta = datetime.datetime.utcnow() - datetime.datetime.fromtimestamp(timestamp)
+        remainder_minutes = math.floor(delta.total_seconds() / 60)
+        adjusted_amount = amount * ((1 - self.r_min) ** remainder_minutes)
+        logg.debug('adjusted for {} minutes {} -> {} delta {}'.format(remainder_minutes, amount, adjusted_amount, amount - adjusted_amount))
+
+        return adjusted_amount
+
+
+    @staticmethod
+    def from_contract(rpc, chain_spec, contract_address, sender_address=ZERO_ADDRESS):
+        c = DemurrageToken(chain_spec)
+        o = c.tax_level(contract_address, sender_address=sender_address)
+        r = rpc.do(o)
+        taxlevel_i = c.parse_tax_level(r)
+
+        o = c.resolution_factor(contract_address, sender_address=sender_address)
+        r = rpc.do(o)
+        divider = c.parse_resolution_factor(r)
+        logg.debug('taxlevel {} f {}'.format(taxlevel_i, divider))
+        taxlevel_f = taxlevel_i / divider
+        return DemurrageCalculator(taxlevel_f)

python/erc20_demurrage_token/runnable/apply.py

@@ -0,0 +1,152 @@
+"""Deploy sarafu token
+
+.. moduleauthor:: Louis Holbrook <dev@holbrook.no>
+.. pgp:: 0826EDA1702D1E87C6E2875121D2E7BB88C2A746 
+
+"""
+
+# standard imports
+import sys
+import os
+import json
+import argparse
+import logging
+import datetime
+import math
+
+# external imports
+import confini
+import chainlib.eth.cli
+from chainlib.eth.block import (
+        block_latest,
+        block_by_number,
+        Block,
+        )
+from chainlib.eth.connection import EthHTTPConnection
+from chainlib.eth.tx import receipt
+from chainlib.eth.constant import ZERO_ADDRESS
+from hexathon import to_int as hex_to_int
+import chainlib.eth.cli
+from chainlib.eth.settings import process_settings
+from chainlib.settings import ChainSettings
+from chainlib.eth.cli.arg import (
+        Arg,
+        ArgFlag,
+        process_args,
+        )
+from chainlib.eth.cli.config import (
+        Config,
+        process_config,
+        )
+from chainlib.eth.cli.log import process_log
+
+# local imports
+import erc20_demurrage_token
+from erc20_demurrage_token import (
+        DemurrageToken,
+        DemurrageTokenSettings,
+        )
+
+logg = logging.getLogger()
+
+
+def process_config_local(config, arg, args, flags):
+    config.add(args.steps, '_STEPS', False)
+    return config
+
+
+arg_flags = ArgFlag()
+arg = Arg(arg_flags)
+flags = arg_flags.STD_WRITE | arg_flags.EXEC | arg_flags.WALLET
+
+argparser = chainlib.eth.cli.ArgumentParser()
+argparser = process_args(argparser, arg, flags)
+argparser.add_argument('--steps', type=int, default=0, help='Max demurrage steps to apply per round')
+args = argparser.parse_args()
+
+logg = process_log(args, logg)
+
+config = Config()
+config = process_config(config, arg, args, flags)
+config = process_config_local(config, arg, args, flags)
+logg.debug('config loaded:\n{}'.format(config))
+
+settings = ChainSettings()
+settings = process_settings(settings, config)
+logg.debug('settings loaded:\n{}'.format(settings))
+
+
+def main():
+    chain_spec = settings.get('CHAIN_SPEC')
+    conn = settings.get('CONN')
+    o = block_latest()
+    r = conn.do(o)
+ 
+    block_start_number = None
+    try:
+        block_start_number = hex_to_int(r)
+    except TypeError:
+        block_start_number = int(r)
+
+    o = block_by_number(block_start_number)
+    r = conn.do(o)
+
+    block_start = Block(r)
+    block_start_timestamp = block_start.timestamp
+    block_start_datetime = datetime.datetime.fromtimestamp(block_start_timestamp)
+
+    gas_oracle = settings.get('FEE_ORACLE')
+    c = DemurrageToken(chain_spec, gas_oracle=gas_oracle)
+    o = c.demurrage_timestamp(settings.get('EXEC'))
+    r = conn.do(o)
+
+    demurrage_timestamp = None
+    try:
+        demurrage_timestamp = hex_to_int(r)
+    except TypeError:
+        demurrage_timestamp = int(r)
+    demurrage_datetime = datetime.datetime.fromtimestamp(demurrage_timestamp)
+
+    total_seconds = block_start_timestamp - demurrage_timestamp
+    total_steps = total_seconds / 60
+
+    if total_steps < 1.0:
+        logg.error('only {} seconds since last demurrage application, skipping'.format(total_seconds))
+        return
+
+    logg.debug('block start is at {} demurrage is at {} -> {} minutes'.format(
+        block_start_datetime,
+        demurrage_datetime,
+        total_steps,
+        ))
+
+    rounds = 1
+    if config.get('_STEPS') > 0:
+        rounds = math.ceil(total_steps / config.get('_STEPS'))
+
+    logg.info('will perform {} rounds of {} steps'.format(rounds, config.get('_STEPS')))
+
+    last_tx_hash = None
+    for i in range(rounds):
+        signer = settings.get('SIGNER')
+        signer_address = settings.get('SENDER_ADDRESS')
+
+        nonce_oracle = settings.get('NONCE_ORACLE')
+
+        c = DemurrageToken(chain_spec, signer=signer, gas_oracle=gas_oracle, nonce_oracle=nonce_oracle)
+        (tx_hash_hex, o) = c.apply_demurrage(config.get('_EXEC_ADDRESS'), signer_address, limit=config.get('_STEPS'))
+        if settings.get('RPC_SEND'):
+            print(tx_hash_hex)
+            conn.do(o)
+            if config.true('_WAIT_ALL') or (i == rounds - 1 and config.true('_WAIT')):
+                r = conn.wait(tx_hash_hex)
+                if r['status'] == 0:
+                    sys.stderr.write('EVM revert while deploying contract. Wish I had more to tell you')
+                    sys.exit(1)
+        else:
+            print(o)
+
+
+
+if __name__ == '__main__':
+    main()

python/erc20_demurrage_token/runnable/deploy.py

@@ -14,151 +14,100 @@ import logging
 
 # external imports
 import confini
-from crypto_dev_signer.eth.signer import ReferenceSigner as EIP155Signer
-from crypto_dev_signer.keystore.dict import DictKeystore
-from chainlib.chain import ChainSpec
-from chainlib.eth.nonce import (
-        RPCNonceOracle,
-        OverrideNonceOracle,
-        )
-from chainlib.eth.gas import (
-        RPCGasOracle,
-        OverrideGasOracle,
-        )
 from chainlib.eth.connection import EthHTTPConnection
 from chainlib.eth.tx import receipt
 from chainlib.eth.constant import ZERO_ADDRESS
+import chainlib.eth.cli
+from chainlib.eth.settings import process_settings
+from chainlib.settings import ChainSettings
+from chainlib.eth.cli.arg import (
+        Arg,
+        ArgFlag,
+        process_args,
+        )
+from chainlib.eth.cli.config import (
+        Config,
+        process_config,
+        )
+from chainlib.eth.cli.log import process_log
 
 # local imports
+import erc20_demurrage_token
 from erc20_demurrage_token import (
         DemurrageToken,
         DemurrageTokenSettings,
         )
 
-logging.basicConfig(level=logging.WARNING)
 logg = logging.getLogger()
 
-script_dir = os.path.dirname(__file__)
-data_dir = os.path.join(script_dir, '..', 'data')
 
-default_config_dir = os.environ.get('CONFINI_DIR', '/usr/local/share/sarafu-token')
+def process_config_local(config, arg, args, flags):
+    config.add(args.token_name, 'TOKEN_NAME', False)
+    config.add(args.token_symbol, 'TOKEN_SYMBOL', False)
+    config.add(args.token_decimals, 'TOKEN_DECIMALS', False)
+    config.add(args.sink_address, 'TOKEN_SINK_ADDRESS', False)
+    config.add(args.redistribution_period, 'TOKEN_REDISTRIBUTION_PERIOD', False)
+    config.add(args.demurrage_level, 'TOKEN_DEMURRAGE_LEVEL', False)
+    config.add(0, 'TOKEN_SUPPLY_LIMIT', False)
+    return config
 
-argparser = argparse.ArgumentParser()
-argparser.add_argument('-c', '--config', dest='c', type=str, default=default_config_dir, help='configuration directory')
-argparser.add_argument('-p', '--provider', dest='p', default='http://localhost:8545', type=str, help='Web3 provider url (http only)')
-argparser.add_argument('-w', action='store_true', help='Wait for the last transaction to be confirmed')
-argparser.add_argument('-ww', action='store_true', help='Wait for every transaction to be confirmed')
-argparser.add_argument('-i', '--chain-spec', dest='i', type=str, default='evm:ethereum:1', help='Chain specification string')
-argparser.add_argument('-y', '--key-file', dest='y', type=str, help='Ethereum keystore file to use for signing')
-argparser.add_argument('-v', action='store_true', help='Be verbose')
-argparser.add_argument('-vv', action='store_true', help='Be more verbose')
-argparser.add_argument('-d', action='store_true', help='Dump RPC calls to terminal and do not send')
-argparser.add_argument('--name', type=str, help='Token name')
-argparser.add_argument('--decimals', default=6, type=int, help='Token decimals')
-argparser.add_argument('--gas-price', type=int, dest='gas_price', help='Override gas price')
-argparser.add_argument('--nonce', type=int, help='Override transaction nonce')
-argparser.add_argument('--sink-address', dest='sink_address', default=ZERO_ADDRESS, type=str, help='demurrage level,ppm per minute') 
-argparser.add_argument('--supply-limit', dest='supply_limit', type=int, help='token supply limit (0 = no limit)')
-argparser.add_argument('--redistribution-period', type=int, help='redistribution period, minutes (0 = deactivate)') # default 10080 = week
-argparser.add_argument('--env-prefix', default=os.environ.get('CONFINI_ENV_PREFIX'), dest='env_prefix', type=str, help='environment prefix for variables to overwrite configuration')
-argparser.add_argument('--symbol', type=str, help='Token symbol')
+
+arg_flags = ArgFlag()
+arg = Arg(arg_flags)
+flags = arg_flags.STD_WRITE | arg_flags.EXEC | arg_flags.WALLET
+
+argparser = chainlib.eth.cli.ArgumentParser()
+argparser = process_args(argparser, arg, flags)
+argparser.add_argument('--name', dest='token_name', type=str, help='Token name')
+argparser.add_argument('--symbol', dest='token_symbol', required=True, type=str, help='Token symbol')
+argparser.add_argument('--decimals', dest='token_decimals', type=int, help='Token decimals')
+argparser.add_argument('--sink-address', dest='sink_address', type=str, help='demurrage level,ppm per minute') 
+#argparser.add_argument('--supply-limit', dest='supply_limit', type=int, help='token supply limit (0 = no limit)')
+argparser.add_argument('--redistribution-period', dest='redistribution_period', type=int, help='redistribution period, minutes (0 = deactivate)') # default 10080 = week
+#argparser.add_argument('--multi', action='store_true', help='automatic redistribution')
 argparser.add_argument('--demurrage-level', dest='demurrage_level', type=int, help='demurrage level, ppm per minute') 
 args = argparser.parse_args()
 
-if args.vv:
-    logg.setLevel(logging.DEBUG)
-elif args.v:
-    logg.setLevel(logging.INFO)
+logg = process_log(args, logg)
 
-block_all = args.ww
-block_last = args.w or block_all
-
-# process config
-config = confini.Config(args.c)
-config.process()
-args_override = {
-            'TOKEN_REDISTRIBUTION_PERIOD': getattr(args, 'redistribution_period'),
-            'TOKEN_DEMURRAGE_LEVEL': getattr(args, 'demurrage_level'),
-            'TOKEN_SUPPLY_LIMIT': getattr(args, 'supply_limit'),
-            'TOKEN_SYMBOL': getattr(args, 'symbol'),
-            'TOKEN_NAME': getattr(args, 'name'),
-            'TOKEN_DECIMALS': getattr(args, 'decimals'),
-            'TOKEN_SINK_ADDRESS': getattr(args, 'sink_address'),
-            'SESSION_CHAIN_SPEC': getattr(args, 'i'),
-            'ETH_PROVIDER': getattr(args, 'p'),
-        }
-if config.get('TOKEN_NAME') == None:
-    logg.info('token name not set, using symbol {} as name'.format(config.get('TOKEN_SYMBOL')))
-    config.add(config.get('TOKEN_SYMBOL'), 'TOKEN_NAME', True)
-config.dict_override(args_override, 'cli args')
-
-if config.get('TOKEN_SUPPLY_LIMIT') == None:
-    config.add(0, 'TOKEN_SUPPLY_LIMIT', True)
-
-if config.get('TOKEN_REDISTRIBUTION_PERIOD') == None:
-    config.add(10800, 'TOKEN_REDISTRIBUTION_PERIOD', True)
+config = Config()
+config = process_config(config, arg, args, flags)
+config = process_config_local(config, arg, args, flags)
 logg.debug('config loaded:\n{}'.format(config))
 
-passphrase_env = 'ETH_PASSPHRASE'
-if args.env_prefix != None:
-    passphrase_env = args.env_prefix + '_' + passphrase_env
-passphrase = os.environ.get(passphrase_env)
-if passphrase == None:
-    logg.warning('no passphrase given')
-    passphrase=''
+settings = ChainSettings()
+settings = process_settings(settings, config)
+logg.debug('settings loaded:\n{}'.format(settings))
 
-signer_address = None
-keystore = DictKeystore()
-if args.y != None:
-    logg.debug('loading keystore file {}'.format(args.y))
-    signer_address = keystore.import_keystore_file(args.y, password=passphrase)
-    logg.debug('now have key for signer address {}'.format(signer_address))
-signer = EIP155Signer(keystore)
-
-chain_spec = ChainSpec.from_chain_str(args.i)
-
-rpc = EthHTTPConnection(args.p)
-nonce_oracle = None
-if args.nonce != None:
-    nonce_oracle = OverrideNonceOracle(signer_address, args.nonce)
-else:
-    nonce_oracle = RPCNonceOracle(signer_address, rpc)
-
-gas_oracle = None
-if args.gas_price !=None:
-    gas_oracle = OverrideGasOracle(price=args.gas_price, conn=rpc, code_callback=DemurrageToken.gas)
-else:
-    gas_oracle = RPCGasOracle(rpc, code_callback=DemurrageToken.gas)
-
-dummy = args.d
-
-token_name = args.name
-if token_name == None:
-    token_name = args.symbol
 
 def main():
+    chain_spec = settings.get('CHAIN_SPEC')
+    conn = settings.get('CONN')
+    signer = settings.get('SIGNER')
+    signer_address = settings.get('SENDER_ADDRESS')
+
+    gas_oracle = settings.get('FEE_ORACLE')
+    nonce_oracle = settings.get('NONCE_ORACLE')
+
     c = DemurrageToken(chain_spec, signer=signer, gas_oracle=gas_oracle, nonce_oracle=nonce_oracle)
-    settings = DemurrageTokenSettings()
-    settings.name = config.get('TOKEN_NAME')
-    settings.symbol = config.get('TOKEN_SYMBOL')
-    settings.decimals = int(config.get('TOKEN_DECIMALS'))
-    settings.demurrage_level = int(config.get('TOKEN_DEMURRAGE_LEVEL'))
-    settings.period_minutes = int(config.get('TOKEN_REDISTRIBUTION_PERIOD'))
-    settings.sink_address = config.get('TOKEN_SINK_ADDRESS')
+    token_settings = DemurrageTokenSettings()
+    token_settings.name = config.get('TOKEN_NAME')
+    token_settings.symbol = config.get('TOKEN_SYMBOL')
+    token_settings.decimals = int(config.get('TOKEN_DECIMALS'))
+    token_settings.demurrage_level = int(config.get('TOKEN_DEMURRAGE_LEVEL'))
+    token_settings.period_minutes = int(config.get('TOKEN_REDISTRIBUTION_PERIOD'))
+    token_settings.sink_address = config.get('TOKEN_SINK_ADDRESS')
 
     (tx_hash_hex, o) = c.constructor(
             signer_address,
-            settings,
-            redistribute=settings.period_minutes > 0,
+            token_settings,
+            redistribute=config.true('_MULTI'),
             cap=int(config.get('TOKEN_SUPPLY_LIMIT')),
             )
-    if dummy:
-        print(tx_hash_hex)
-        print(o)
-    else:
-        rpc.do(o)
-        if block_last:
-            r = rpc.wait(tx_hash_hex)
+    if settings.get('RPC_SEND'):
+        conn.do(o)
+        if config.true('_WAIT'):
+            r = conn.wait(tx_hash_hex)
             if r['status'] == 0:
                 sys.stderr.write('EVM revert while deploying contract. Wish I had more to tell you')
                 sys.exit(1)
@@ -169,6 +118,9 @@ def main():
         else:
             print(tx_hash_hex)
 
+    else:
+        print(o)
+
 
 if __name__ == '__main__':
     main()

python/erc20_demurrage_token/sim/sim.py

@@ -20,8 +20,8 @@ from chainlib.eth.block import (
         block_by_number,
         block_by_hash,
         )
-from crypto_dev_signer.keystore.dict import DictKeystore
-from crypto_dev_signer.eth.signer import ReferenceSigner as EIP155Signer
+from funga.eth.keystore.dict import DictKeystore
+from funga.eth.signer import EIP155Signer
 from hexathon import (
         strip_0x,
         add_0x,

python/erc20_demurrage_token/token.py

@@ -38,6 +38,15 @@ class DemurrageTokenSettings:
         self.sink_address = None
 
 
+    def __str__(self):
+        return 'name {} demurrage level {} period minutes {} sink address {}'.format(
+                self.name,
+                self.demurrage_level,
+                self.period_minutes,
+                self.sink_address,
+                )
+
+
 class DemurrageToken(ERC20):
 
     __abi = {}
@@ -108,6 +117,34 @@ class DemurrageToken(ERC20):
         return DemurrageToken.__bytecode[name]
 
 
+    def increase_allowance(self, contract_address, sender_address, address, value, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('increaseAllowance')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.typ(ABIContractType.UINT256)
+        enc.address(address)
+        enc.uint256(value)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+
+
+    def decrease_allowance(self, contract_address, sender_address, address, value, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('decreaseAllowance')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.typ(ABIContractType.UINT256)
+        enc.address(address)
+        enc.uint256(value)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+
+
     def add_minter(self, contract_address, sender_address, address, tx_format=TxFormat.JSONRPC):
         enc = ABIContractEncoder()
         enc.method('addMinter')
@@ -146,6 +183,33 @@ class DemurrageToken(ERC20):
         return tx
 
 
+    def burn(self, contract_address, sender_address, value, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('burn')
+        enc.typ(ABIContractType.UINT256)
+        enc.uint256(value)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+
+
+    def total_burned(self, contract_address, sender_address=ZERO_ADDRESS, id_generator=None):
+        j = JSONRPCRequest(id_generator)
+        o = j.template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('totalBurned')
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        o = j.finalize(o)
+        return o
+
+
     def to_base_amount(self, contract_address, value, sender_address=ZERO_ADDRESS, id_generator=None):
         j = JSONRPCRequest(id_generator)
         o = j.template()
@@ -325,8 +389,19 @@ class DemurrageToken(ERC20):
         return o
 
 
-    def apply_demurrage(self, contract_address, sender_address):
-        return self.transact_noarg('applyDemurrage', contract_address, sender_address)
+    def apply_demurrage(self, contract_address, sender_address, limit=0, tx_format=TxFormat.JSONRPC):
+        if limit == 0:
+            return self.transact_noarg('applyDemurrage', contract_address, sender_address)
+
+        enc = ABIContractEncoder()
+        enc.method('applyDemurrageLimited')
+        enc.typ(ABIContractType.UINT256)
+        enc.uint256(limit)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
 
 
     def change_period(self, contract_address, sender_address):
@@ -343,7 +418,15 @@ class DemurrageToken(ERC20):
         tx = self.set_code(tx, data)
         tx = self.finalize(tx, tx_format)
         return tx
-    
+
+
+    def tax_level(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('taxLevel', contract_address, sender_address=sender_address)
+
+
+    def resolution_factor(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('resolutionFactor', contract_address, sender_address=sender_address)
+
 
     def actual_period(self, contract_address, sender_address=ZERO_ADDRESS):
         return self.call_noarg('actualPeriod', contract_address, sender_address=sender_address)
@@ -361,6 +444,10 @@ class DemurrageToken(ERC20):
         return self.call_noarg('demurrageAmount', contract_address, sender_address=sender_address)
 
 
+    def demurrage_timestamp(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('demurrageTimestamp', contract_address, sender_address=sender_address)
+
+
     def supply_cap(self, contract_address, sender_address=ZERO_ADDRESS):
         return self.call_noarg('supplyCap', contract_address, sender_address=sender_address)
 
@@ -494,6 +581,7 @@ class DemurrageToken(ERC20):
     def parse_supply_cap(self, v):
         return abi_decode_single(ABIContractType.UINT256, v)
 
+
     @classmethod
     def parse_grow_by(self, v):
         return abi_decode_single(ABIContractType.UINT256, v)
@@ -507,3 +595,18 @@ class DemurrageToken(ERC20):
     @classmethod
     def parse_get_distribution(self, v):
         return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_tax_level(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_resolution_factor(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_total_burned(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)

python/erc20_demurrage_token/unittest/__init__.py

@@ -0,0 +1 @@
+from .base import *

python/erc20_demurrage_token/unittest/base.py

@@ -12,6 +12,7 @@ from chainlib.eth.block import (
         block_by_number,
         )
 from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.constant import ZERO_ADDRESS
 
 # local imports
 from erc20_demurrage_token import (
@@ -19,7 +20,7 @@ from erc20_demurrage_token import (
         DemurrageToken,
         )
 
-logg = logging.getLogger()
+logg = logging.getLogger(__name__)
 
 #BLOCKTIME = 5 # seconds
 TAX_LEVEL = int(10000 * 2) # 2%
@@ -29,64 +30,92 @@ TAX_LEVEL = int(10000 * 2) # 2%
 PERIOD = 10
 
 
-class TestDemurrage(EthTesterCase):
+class TestTokenDeploy:
 
-    def setUp(self):
-        super(TestDemurrage, self).setUp()
+    def __init__(self, rpc, token_symbol='FOO', token_name='Foo Token', sink_address=ZERO_ADDRESS, supply=10**12, tax_level=TAX_LEVEL, period=PERIOD):
+        self.tax_level = tax_level
+        self.period_seconds = period * 60
 
-        self.tax_level = TAX_LEVEL
-        self.period_seconds = PERIOD * 60
-
-        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         self.settings = DemurrageTokenSettings()
-        self.settings.name = 'Foo Token'
-        self.settings.symbol = 'FOO'
+        self.settings.name = token_name
+        self.settings.symbol = token_symbol
         self.settings.decimals = 6
-        self.settings.demurrage_level = TAX_LEVEL * (10 ** 32)
-        self.settings.period_minutes = PERIOD
-        self.settings.sink_address = self.accounts[9]
+        self.settings.demurrage_level = tax_level * (10 ** 32)
+        self.settings.period_minutes = period
+        self.settings.sink_address = sink_address
         self.sink_address = self.settings.sink_address
+        logg.debug('using demurrage token settings: {}'.format(self.settings))
 
         o = block_latest()
-        self.start_block = self.rpc.do(o)
+        self.start_block = rpc.do(o)
         
         o = block_by_number(self.start_block, include_tx=False)
-        r = self.rpc.do(o)
+        r = rpc.do(o)
 
         try:
             self.start_time = int(r['timestamp'], 16)
         except TypeError:
             self.start_time = int(r['timestamp'])
 
-        self.default_supply = 10 ** 12
+        self.default_supply = supply
         self.default_supply_cap = int(self.default_supply * 10)
 
 
-    def deploy(self, interface, mode):
+    def deploy(self, rpc, deployer_address, interface, mode, supply_cap=10**12):
         tx_hash = None
         o = None
+        logg.debug('mode {} {}'.format(mode, self.settings))
+        self.mode = mode
         if mode == 'MultiNocap':
-            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=True, cap=0)
+            (tx_hash, o) = interface.constructor(deployer_address, self.settings, redistribute=True, cap=0)
         elif mode == 'SingleNocap':
-            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=False, cap=0)
+            (tx_hash, o) = interface.constructor(deployer_address, self.settings, redistribute=False, cap=0)
         elif mode == 'MultiCap':
-            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=True, cap=self.default_supply_cap)
+            (tx_hash, o) = interface.constructor(deployer_address, self.settings, redistribute=True, cap=supply_cap)
         elif mode == 'SingleCap':
-            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=False, cap=self.default_supply_cap)
+            (tx_hash, o) = interface.constructor(deployer_address, self.settings, redistribute=False, cap=supply_cap)
         else:
-            raise ValueError('Invalid mode "{}", valid are {}'.format(self.mode, DemurrageToken.valid_modes))
+            raise ValueError('Invalid mode "{}", valid are {}'.format(mode, DemurrageToken.valid_modes))
 
-        r = self.rpc.do(o)
+        r = rpc.do(o)
         o = receipt(tx_hash)
-        r = self.rpc.do(o)
-        self.assertEqual(r['status'], 1)
+        r = rpc.do(o)
+        assert r['status'] == 1
         self.start_block = r['block_number']
         self.address = r['contract_address']
 
         o = block_by_number(r['block_number'])
-        r = self.rpc.do(o)
+        r = rpc.do(o)
         self.start_time = r['timestamp']
 
+        return self.address
+
+
+class TestDemurrage(EthTesterCase):
+
+    def setUp(self):
+        super(TestDemurrage, self).setUp()
+        period = PERIOD
+        try:
+            period = getattr(self, 'period')
+        except AttributeError as e:
+            pass
+        self.deployer = TestTokenDeploy(self.rpc, period=period)
+        self.default_supply = self.deployer.default_supply
+        self.default_supply_cap = self.deployer.default_supply_cap
+        self.start_block = None
+        self.address = None
+        self.start_time = None
+
+
+    def deploy(self, interface, mode):
+        self.address = self.deployer.deploy(self.rpc, self.accounts[0], interface, mode, supply_cap=self.default_supply_cap)
+        self.start_block = self.deployer.start_block
+        self.start_time = self.deployer.start_time
+        self.tax_level = self.deployer.tax_level
+        self.period_seconds = self.deployer.period_seconds
+        self.sink_address = self.deployer.sink_address
+
         logg.debug('contract address {} start block {} start time {}'.format(self.address, self.start_block, self.start_time))
 
 
@@ -97,6 +126,13 @@ class TestDemurrage(EthTesterCase):
         logg.debug('asserted within lower {} <= {} <= {}'.format(lower_target, v, target))
 
 
+    def assert_within_greater(self, v, target, tolerance_ppm):
+        higher_target = target + (target * (tolerance_ppm / 1000000))
+        self.assertLessEqual(v, higher_target)
+        self.assertGreaterEqual(v, target)
+        logg.debug('asserted within lower {} <= {} <= {}'.format(target, v, higher_target))
+
+
     def tearDown(self):
         pass
 
@@ -173,10 +209,11 @@ class TestDemurrageCap(TestDemurrage):
 class TestDemurrageUnit(TestDemurrage):
 
     def setUp(self):
-        super(TestDemurrage, self).setUp()
+        self.period = 1
+        self.period_seconds = self.period * 60
+        self.tax_level = TAX_LEVEL
 
-        self.tax_level = 50
-        self.period_seconds = 60
+        super(TestDemurrageUnit, self).setUp()
 
         nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         self.settings = DemurrageTokenSettings()

python/requirements.txt

@@ -1,3 +1,3 @@
-chainlib~=0.0.5a1
-eth-erc20~=0.0.10a1
-crypto-dev-signer~=0.4.14b6
+chainlib-eth~=0.4.6
+eth-erc20~=0.5.1
+funga-eth~=0.6.0

python/run_tests.sh

@@ -1,25 +1,35 @@
 #!/bin/bash
 
+set -x
 set -e
 
 export PYTHONPATH=.
 
 #modes=(MultiNocap MultiCap SingleCap SingleNocap)
-modes=(SingleCap SingleNocap) # other contracts need to be updted
+#modes=(SingleCap SingleNocap) # other contracts need to be updted
+modes=(SingleNocap) # other contracts need to be updted
 for m in ${modes[@]}; do
 	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_basic.py
 	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_growth.py
 	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_amounts.py
 	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_single.py
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_burn.py
 done
 
-modes=(SingleCap) # other contracts need to be updted
+#modes=(SingleCap) # other contracts need to be updted
+modes=()
 for m in ${modes[@]}; do
 	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_period.py
-	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_redistribution_unit.py
 done
 
-modes=(MultiCap SingleCap)
+modes=(SingleNocap) # other contracts need to be updted
+for m in ${modes[@]}; do
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_redistribution_unit.py
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_redistribution_single.py
+done
+
+#modes=(MultiCap SingleCap)
+modes=()
 for m in ${modes[@]}; do
 	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_cap.py
 done
@@ -31,3 +41,4 @@ done
 #done
 
 set +e
+set +x

python/setup.cfg

@@ -1,10 +1,10 @@
 [metadata]
 name = erc20-demurrage-token
-version = 0.0.2a1
+version = 0.2.0
 description = ERC20 token with redistributed continual demurrage
 author = Louis Holbrook
 author_email = dev@holbrook.no
-url = https://gitlab.com/grassrootseconomics/sarafu-token
+url = https://gitlab.com/ccicnet/erc20-demurrage-token
 keywords =
 	ethereum
 	blockchain
@@ -25,12 +25,13 @@ licence_files =
 
 [options]
 include_package_data = True
-python_requires = >= 3.6
+python_requires = >= 3.7
 packages =
 	erc20_demurrage_token
 	erc20_demurrage_token.runnable
 	erc20_demurrage_token.data
 	erc20_demurrage_token.sim
+	erc20_demurrage_token.unittest
 
 [options.package_data]
 * =
@@ -40,3 +41,4 @@ packages =
 [options.entry_points]
 console_scripts =
 	erc20-demurrage-token-deploy = erc20_demurrage_token.runnable.deploy:main
+	erc20-demurrage-token-apply = erc20_demurrage_token.runnable.apply:main

python/tests/test_amounts.py

@@ -13,7 +13,7 @@ from chainlib.eth.tx import receipt
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageDefault
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()

python/tests/test_basic.py

@@ -18,7 +18,7 @@ from chainlib.eth.block import (
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageDefault
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
@@ -28,179 +28,205 @@ testdir = os.path.dirname(__file__)
 
 class TestBasic(TestDemurrageDefault):
 
-#    def test_hello(self):
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        o = c.actual_period(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        
-#        self.backend.time_travel(self.start_time + self.period_seconds + 1)
-#        o = c.actual_period(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#
-#
-#    def test_balance(self):
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
-#        r = self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 1024)
-#
-#
-#    def test_apply_demurrage(self):
-#        modifier = (10 ** 38)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#
-#        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        demurrage_amount = c.parse_demurrage_amount(r)
-#        self.assertEqual(modifier, demurrage_amount)
-#
-#        o = block_latest()
-#        r = self.rpc.do(o)
-#        o = block_by_number(r)
-#        b = self.rpc.do(o)
-#        logg.debug('block {} start {}'.format(b['timestamp'], self.start_time))
-#
-#        self.backend.time_travel(self.start_time + 2)
-#        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        demurrage_amount = c.parse_demurrage_amount(r)
-#        self.assertEqual(modifier, demurrage_amount)
-#
-#        self.backend.time_travel(self.start_time + 61)
-#        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        demurrage_amount = c.parse_demurrage_amount(r)
-#        modifier_base = 1000000 - self.tax_level
-#        logg.debug('modifier base {}'.format(modifier_base))
-#        modifier = int(modifier_base * (10 ** 32)) # 38 decimal places minus 6 (1000000)
-#        self.assertEqual(modifier, demurrage_amount)
-#
-#        self.backend.time_travel(self.start_time + 601)
-#        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        demurrage_amount = c.parse_demurrage_amount(r)
-#        modifier_base = ((1000000 - self.tax_level) / 1000000) ** 10
-#        modifier = int(modifier_base * (10 ** 12))
-#
-#        rounding_tolerance_nano = 4000000 # 0.000004% precision
-#        demurrage_amount_truncate = int(demurrage_amount / (10 ** 26)) # equals 12 decimal places
-#        self.assertGreaterEqual(modifier, demurrage_amount_truncate - rounding_tolerance_nano)
-#        self.assertLessEqual(modifier, demurrage_amount_truncate)
-#
-#
-#    def test_mint(self):
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
-#        r = self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 1024)
-#
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 976)
-#        r = self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 2000)
-#
-#
-#        self.backend.time_travel(self.start_time + 61)
-#        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, int(2000 * 0.98))
-#
-#
-#    def test_minter_control(self):
-#        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 0)
-#            
-#        (tx_hash, o) = c.add_minter(self.address, self.accounts[1], self.accounts[1])
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 0)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.add_minter(self.address, self.accounts[0], self.accounts[1])
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        (tx_hash, o) = c.add_minter(self.address, self.accounts[1], self.accounts[2])
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 0)
-#
-#        (tx_hash, o) = c.remove_minter(self.address, self.accounts[1], self.accounts[1])
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 0)
-#            
-#
+    def test_hello(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+
+
+    def test_balance(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 1024)
+
+
+    def test_apply_demurrage_limited(self):
+        modifier = (10 ** 28)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        self.assertEqual(modifier, demurrage_amount)
+
+        self.backend.time_travel(self.start_time + 120)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0], limit=1)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        modifier_base = 1000000 - self.tax_level
+        modifier = int(modifier_base * (10 ** 22)) # 38 decimal places minus 6 (1000000)
+        self.assertEqual(modifier, demurrage_amount)
+
+
+    def test_apply_demurrage(self):
+        modifier = (10 ** 28)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        self.assertEqual(modifier, demurrage_amount)
+
+        o = block_latest()
+        r = self.rpc.do(o)
+        o = block_by_number(r)
+        b = self.rpc.do(o)
+        logg.debug('block {} start {}'.format(b['timestamp'], self.start_time))
+
+        self.backend.time_travel(self.start_time + 2)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        self.assertEqual(modifier, demurrage_amount)
+
+        self.backend.time_travel(self.start_time + 61)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        modifier_base = 1000000 - self.tax_level
+        modifier = int(modifier_base * (10 ** 22)) # 38 decimal places minus 6 (1000000)
+        self.assertEqual(modifier, demurrage_amount)
+
+        self.backend.time_travel(self.start_time + 601)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        modifier_base = ((1000000 - self.tax_level) / 1000000) ** 10
+        logg.warning('mod base {}'.format(modifier_base))
+        modifier = int(modifier_base * (10 ** 12))
+
+        rounding_tolerance_nano = 4000000 # 0.000004% precision
+        demurrage_amount_truncate = int(demurrage_amount / (10 ** 16)) # equals 38 decimal places - 14 for the modifier magniture - 2 for percent int calc + 6 for token decimals <- TODO verify this calc
+        self.assertGreaterEqual(modifier, demurrage_amount_truncate - rounding_tolerance_nano)
+        self.assertLessEqual(modifier, demurrage_amount_truncate)
+
+
+    def test_mint(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 1024)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 976)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 2000)
+
+
+        self.backend.time_travel(self.start_time + 61)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, int(2000 * 0.98))
+
+
+    def test_minter_control(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+            
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[1], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[0], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[1], self.accounts[2])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+        (tx_hash, o) = c.remove_minter(self.address, self.accounts[1], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+            
+
     def test_base_amount(self):
         nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
@@ -216,78 +242,129 @@ class TestBasic(TestDemurrageDefault):
         amount = c.parse_to_base_amount(r)
         self.assertEqual(amount, 1020)
 
-#
-#    def test_transfer(self):
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
-#        self.rpc.do(o)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.transfer(self.address, self.accounts[1], self.accounts[2], 500)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 524)
-#
-#        o = c.balance_of(self.address, self.accounts[2], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 500)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.transfer(self.address, self.accounts[2], self.accounts[1], 500)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#
-#       
-#
-#    def test_transfer_from(self):
-#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
-#        self.rpc.do(o)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.approve(self.address, self.accounts[1], self.accounts[2], 500)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-#        
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 1024)
-#
-#        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
-#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
-#        (tx_hash, o) = c.transfer_from(self.address, self.accounts[2], self.accounts[1], self.accounts[3], 500)
-#        self.rpc.do(o)
-#        o = receipt(tx_hash)
-#        r = self.rpc.do(o)
-#        self.assertEqual(r['status'], 1)
-# 
-#        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 524)
-#
-#        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        balance = c.parse_balance_of(r)
-#        self.assertEqual(balance, 500)
+
+    def test_transfer(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        self.rpc.do(o)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[1], self.accounts[2], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 524)
+
+        o = c.balance_of(self.address, self.accounts[2], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 500)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[2], self.accounts[1], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+      
+    def test_approve(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.approve(self.address, self.accounts[0], self.accounts[1], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+ 
+        (tx_hash, o) = c.approve(self.address, self.accounts[0], self.accounts[1], 600)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+        (tx_hash, o) = c.approve(self.address, self.accounts[0], self.accounts[1], 0)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.approve(self.address, self.accounts[0], self.accounts[1], 600)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.increase_allowance(self.address, self.accounts[0], self.accounts[1], 200)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.decrease_allowance(self.address, self.accounts[0], self.accounts[1], 800)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.approve(self.address, self.accounts[0], self.accounts[1], 42)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+
+    def test_transfer_from(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        self.rpc.do(o)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.approve(self.address, self.accounts[1], self.accounts[2], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 1024)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer_from(self.address, self.accounts[2], self.accounts[1], self.accounts[3], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+ 
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 524)
+
+        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 500)
+
+        (tx_hash, o) = c.transfer_from(self.address, self.accounts[2], self.accounts[1], self.accounts[3], 1)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
 
 
 if __name__ == '__main__':

python/tests/test_burn.py

@@ -0,0 +1,320 @@
+# standard imports
+import os
+import unittest
+import json
+import logging
+import datetime
+
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+from chainlib.eth.block import (
+        block_latest,
+        block_by_number,
+    )
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from erc20_demurrage_token.unittest.base import TestDemurrage
+
+logging.basicConfig(level=logging.INFO)
+logg = logging.getLogger()
+
+testdir = os.path.dirname(__file__)
+
+TAX_LEVEL = 2
+
+class TestBurn(TestDemurrage):
+
+    def setUp(self):
+        super(TestBurn, self).setUp()
+
+
+    def deploy(self, tax_level=None):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        self.mode = os.environ.get('ERC20_DEMURRAGE_TOKEN_TEST_MODE')
+        if self.mode == None:
+            self.mode = 'MultiNocap'
+        logg.debug('executing test setup default mode {}'.format(self.mode))
+
+        if tax_level != None:
+            self.deployer.settings.demurrage_level = tax_level * (10 ** 32)
+        self.deployer.settings.sink_address = self.accounts[9]
+        self.deployer.sink_address = self.accounts[9]
+        super(TestBurn, self).deploy(c, self.mode)
+
+        logg.info('deployed with mode {}'.format(self.mode))
+
+
+    # Burn tokens and immediately check balances and supply
+    def test_burn_basic(self):
+        self.deploy()
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1000000)
+        r = self.rpc.do(o)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.burn(self.address, self.accounts[1], 600000)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[0], self.accounts[1])
+        r = self.rpc.do(o)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.burn(self.address, self.accounts[1], 600000)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+        self.assertEqual(new_supply, 400000)
+
+        o = c.total_burned(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        burned = c.parse_total_burned(r)
+        self.assertEqual(burned, 600000)
+
+
+    # burn tokens and check sink balance and supply after first redistribution period
+    def test_burned_redistribution(self):
+        self.deploy()
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[0], 1000000000)
+        r = self.rpc.do(o)
+
+        (tx_hash, o) = c.burn(self.address, self.accounts[0], 500000000)
+        r = self.rpc.do(o)
+
+        (tx_hash, o) = c.transfer(self.address, self.accounts[0], self.sink_address, 500000000)
+        r = self.rpc.do(o)
+
+        self.backend.time_travel(self.start_time + self.period_seconds)
+
+        o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bal = c.parse_balance(r)
+        self.assertEqual(bal, 416873881) # 9 periods demurrage
+
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+        self.assertEqual(new_supply, 500000000)
+
+        o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bal = c.parse_balance(r)
+        self.assert_within_lower(bal, 500000000, 0.0025)
+
+        self.backend.time_travel(self.start_time + (self.period_seconds * 2))
+
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+        self.assertEqual(new_supply, 500000000)
+
+        # if we don't burn anything more it should be the same 
+        o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bal = c.parse_balance(r)
+        self.assert_within_lower(bal, 500000000, 0.0025)
+
+
+    # burn tokens and check sink and taxed balance and supply after first redistribution period
+    def test_burned_other_redistribution(self):
+        self.deploy()
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[0], 1000000000)
+        r = self.rpc.do(o)
+
+        (tx_hash, o) = c.burn(self.address, self.accounts[0], 500000000)
+        r = self.rpc.do(o)
+
+        (tx_hash, o) = c.transfer(self.address, self.accounts[0], self.accounts[1], 500000000)
+        r = self.rpc.do(o)
+
+        self.backend.time_travel(self.start_time + self.period_seconds)
+
+        o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bal = c.parse_balance(r)
+        self.assertEqual(bal, 416873881) # 9 periods demurrage
+
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+        self.assertEqual(new_supply, 500000000)
+
+        o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bal = c.parse_balance(r)
+        self.assertEqual(bal, 408536403) # 9 periods demurrage
+
+        o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        sink_bal = c.parse_balance(r)
+        self.assert_within_lower(sink_bal, 500000000 - 408536403, 0.09) # TODO is this ok variance, 1.0 is ppm?
+
+        self.backend.time_travel(self.start_time + (self.period_seconds * 2))
+
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+        self.assertEqual(new_supply, 500000000)
+
+        o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        next_bal = c.parse_balance(r)
+        self.assertEqual(next_bal, 333803985) # 9 periods demurrage
+
+        o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        prev_sink_bal = sink_bal
+        bal = prev_sink_bal + (bal - next_bal)
+        sink_bal = c.parse_balance(r)
+        self.assert_within_lower(sink_bal, bal, 0.09) # TODO is this ok variance, 1.0 is ppm?
+
+
+    # verify expected results of balance and supply after multiple redistribution periods
+    def test_burn_accumulate(self):
+        self.deploy(tax_level=2/1000)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[0], self.sink_address)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.sink_address, self.default_supply)
+        r = self.rpc.do(o)
+
+        balance_share = int(self.default_supply / 2)
+        nonce_oracle = RPCNonceOracle(self.sink_address, self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.sink_address, self.accounts[1], balance_share)
+        r = self.rpc.do(o)
+
+        new_supply = None
+        burn_rate = 1000
+        sink_bal = None
+        bob_bal = None
+        bob_refund = None
+
+        o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bob_bal = c.parse_balance(r)
+        prev_bob_bal = bob_bal
+
+        iterations = 100
+
+        for i in range(1, iterations + 1):
+            nonce_oracle = RPCNonceOracle(self.sink_address, self.rpc)
+            c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+            if bob_refund != None:
+                (tx_hash, o) = c.transfer(self.address, self.sink_address, self.accounts[1], bob_refund)
+                r = self.rpc.do(o)
+                o = receipt(tx_hash)
+                r = self.rpc.do(o)
+                self.assertEqual(r['status'], 1)
+
+            (tx_hash, o) = c.burn(self.address, self.sink_address, burn_rate)
+            r = self.rpc.do(o)
+            o = receipt(tx_hash)
+            r = self.rpc.do(o)
+            self.assertEqual(r['status'], 1)
+
+            nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+            c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+            o = c.total_supply(self.address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            new_supply = c.parse_total_supply(r)
+
+            self.backend.time_travel(self.start_time + (self.period_seconds * i))
+
+            (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+            self.rpc.do(o)
+            
+            o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            bob_bal = c.parse_balance(r)
+            bob_refund = prev_bob_bal - bob_bal
+
+            o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            burner_bal = c.parse_balance(r)
+
+            sum_supply = bob_bal + burner_bal
+          
+            o = c.total_burned(self.address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            total_burned = c.parse_balance(r)
+
+            o = c.to_base_amount(self.address, total_burned, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            total_burned_base = c.parse_balance(r)
+
+            expected_supply = self.default_supply - (burn_rate * i)
+            logg.info('checking burn round {} balance burner {} bob {} supply {} expected {} summed {} burned {} base {}'.format(i, burner_bal, bob_bal, new_supply, expected_supply, sum_supply, total_burned, total_burned_base))
+            self.assertEqual(new_supply, expected_supply)
+
+        sum_supply = burner_bal + bob_bal
+        logg.debug('balances sink {} bob {} total {} supply real {} original {}'.format(sink_bal, bob_bal, sum_supply, new_supply, self.default_supply))
+
+        self.assert_within_lower(sum_supply, new_supply, 0.00001)
+        self.assert_within_greater(burner_bal, balance_share - total_burned, 0.1)
+
+        bob_delta = self.default_supply * ((2 / 1000000) / 1000)
+        self.assert_within_lower(bob_bal, balance_share - bob_delta, 0.1)
+        
+        self.assertEqual(total_burned, iterations * burn_rate)
+
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_cap.py

@@ -18,7 +18,7 @@ from hexathon import (
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageCap
+from erc20_demurrage_token.unittest.base import TestDemurrageCap
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()

python/tests/test_demurrage.py

@@ -0,0 +1,133 @@
+# standard imports
+import datetime
+import unittest
+import logging
+import os
+
+# external imports
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+from erc20_demurrage_token.demurrage import DemurrageCalculator
+
+# test imports
+from erc20_demurrage_token.unittest.base import TestDemurrage
+
+logging.basicConfig(level=logging.INFO)
+logg = logging.getLogger()
+
+
+class TestDemurragePeriods(TestDemurrage):
+
+    def setUp(self):
+        super(TestDemurragePeriods, self).setUp()
+   
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        self.mode = os.environ.get('ERC20_DEMURRAGE_TOKEN_TEST_MODE')
+        if self.mode == None:
+            self.mode = 'MultiNocap'
+        logg.debug('executing test setup default mode {}'.format(self.mode))
+
+        self.deployer.settings.demurrage_level = (2 / 1000) * (10 ** 32)
+        self.deployer.settings.sink_address = self.accounts[9]
+        self.deployer.sink_address = self.accounts[9]
+        self.deploy(c, self.mode)
+
+        logg.info('deployed with mode {}'.format(self.mode))
+
+
+    # verify that tax level calculation is in ppm as expected
+    def test_ppm(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], self.default_supply)
+        r = self.rpc.do(o)
+
+        self.backend.time_travel(self.start_time + 60)
+
+        (tx_hash, o) = c.apply_demurrage(self.address, self.accounts[0])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bob_bal = c.parse_balance(r)
+
+        o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        sink_bal = c.parse_balance(r)
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+
+        balance_delta = self.default_supply * ((2 / 1000000) / 1000) 
+        self.assertEqual(bob_bal, self.default_supply - balance_delta)
+
+
+
+    # verify balances and supply after multiple demurrage periods
+    def test_over_time(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], self.default_supply)
+        r = self.rpc.do(o)
+
+        o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bob_bal = c.parse_balance(r)
+        prev_bob_bal = bob_bal
+
+        nonce_oracle = RPCNonceOracle(self.sink_address, self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        iterations = 100
+
+        for i in range(1, iterations + 1):
+            self.backend.time_travel(self.start_time + (self.period_seconds * i))
+
+            (tx_hash, o) = c.transfer(self.address, self.sink_address, self.accounts[1], prev_bob_bal - bob_bal)
+            r = self.rpc.do(o)
+            o = receipt(tx_hash)
+            r = self.rpc.do(o)
+            self.assertEqual(r['status'], 1)
+
+            (tx_hash, o) = c.apply_demurrage(self.address, self.sink_address)
+            self.rpc.do(o)
+            o = receipt(tx_hash)
+            r = self.rpc.do(o)
+            self.assertEqual(r['status'], 1)
+
+            o = c.balance(self.address, self.accounts[1], sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            bob_bal = c.parse_balance(r)
+
+            o = c.balance(self.address, self.sink_address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            sink_bal = c.parse_balance(r)
+
+            o = c.total_supply(self.address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            new_supply = c.parse_total_supply(r)
+
+            logg.info('round {} supply {} balance sink {} bob {}'.format(i, new_supply, sink_bal, bob_bal))
+
+        sum_supply = sink_bal + bob_bal
+
+        bob_delta = self.default_supply * ((2 / 1000000) / 100)
+
+        self.assert_within_lower(sum_supply, new_supply, 0.00001)
+        self.assert_within_greater(bob_bal, self.default_supply - bob_delta, 0.001)
+        self.assert_within_lower(sink_bal, bob_delta, 1000)
+        
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_demurrage_ext.py

@@ -0,0 +1,41 @@
+# standard imports
+import datetime
+import unittest
+
+# external imports
+from chainlib.eth.nonce import RPCNonceOracle
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+from erc20_demurrage_token.demurrage import DemurrageCalculator
+
+# test imports
+from erc20_demurrage_token.unittest.base import TestDemurrage
+
+
+class TestEmulate(TestDemurrage):
+
+    def test_amount_since(self):
+        d = datetime.datetime.utcnow() - datetime.timedelta(seconds=29, hours=5, minutes=3, days=4)
+        c = DemurrageCalculator(0.00000050105908373373)
+        a = c.amount_since(100, d.timestamp())
+        self.assert_within_lower(a, 99.69667, 0.1)
+
+
+    def test_amount_since_slow(self):
+        d = datetime.datetime.utcnow() - datetime.timedelta(seconds=29, hours=5, minutes=3, days=4)
+        c = DemurrageCalculator(0.00000050105908373373)
+        a = c.amount_since_slow(100, d.timestamp())
+        self.assert_within_lower(a, 99.69667, 0.1)
+
+
+    def test_from_contract(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        self.deploy(c, 'SingleNocap')
+        dc = DemurrageCalculator.from_contract(self.rpc, self.chain_spec, self.address, sender_address=self.accounts[0])
+        self.assertEqual(dc.r_min, 0.02)
+
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_growth.py

@@ -18,7 +18,7 @@ from chainlib.eth.block import (
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageDefault
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()

python/tests/test_period.py

@@ -7,13 +7,21 @@ import logging
 # external imports
 from chainlib.eth.constant import ZERO_ADDRESS
 from chainlib.eth.nonce import RPCNonceOracle
-from chainlib.eth.tx import receipt
+from chainlib.eth.tx import (
+        receipt,
+        TxFactory,
+        TxFormat,
+        )
+from chainlib.eth.contract import (
+        ABIContractEncoder,
+        ABIContractType,
+        )
 
 # local imports
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageDefault
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
@@ -103,5 +111,90 @@ class TestPeriod(TestDemurrageDefault):
         self.assertEqual(modifier, period)
 
 
+    def test_change_sink(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        o = c.balance_of(self.address, ZERO_ADDRESS, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 0)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 102400000000)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, ZERO_ADDRESS, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertGreater(balance, 0)
+        old_sink_balance = balance
+
+        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 0)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[5], self.rpc)
+        c = TxFactory(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        enc = ABIContractEncoder()
+        enc.method('setSinkAddress')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(self.accounts[3])
+        data = enc.get()
+        o = c.template(self.accounts[5], self.address, use_nonce=True)
+        o = c.set_code(o, data)
+        (tx_hash, o) = c.finalize(o, TxFormat.JSONRPC)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = TxFactory(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        enc = ABIContractEncoder()
+        enc.method('setSinkAddress')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(self.accounts[3])
+        data = enc.get()
+        o = c.template(self.accounts[0], self.address, use_nonce=True)
+        o = c.set_code(o, data)
+        (tx_hash, o) = c.finalize(o, TxFormat.JSONRPC)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        self.backend.time_travel(self.start_time + (self.period_seconds * 2) + 1)
+
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, ZERO_ADDRESS, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertLess(balance, old_sink_balance)
+
+        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertGreater(balance, 0)
+
+
 if __name__ == '__main__':
     unittest.main()

python/tests/test_redistribution.py

@@ -22,7 +22,7 @@ from hexathon import (
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageDefault
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
@@ -31,6 +31,8 @@ testdir = os.path.dirname(__file__)
 
 class TestRedistribution(TestDemurrageDefault):
 
+
+
     def test_whole_is_parts(self):
         nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)

python/tests/test_redistribution_single.py

@@ -0,0 +1,198 @@
+# standard imports
+import os
+import unittest
+import json
+import logging
+
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+from chainlib.eth.block import (
+        block_latest,
+        block_by_number,
+        )
+from chainlib.eth.address import to_checksum_address
+from hexathon import (
+        strip_0x,
+        add_0x,
+        )
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
+
+logging.basicConfig(level=logging.INFO)
+logg = logging.getLogger()
+
+testdir = os.path.dirname(__file__)
+
+class TestRedistribution(TestDemurrageDefault):
+
+
+    def test_redistribution_periods(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        demurrage = (1 - (self.tax_level / 1000000)) * (10**28)
+        supply = self.default_supply
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[0], supply)
+        self.rpc.do(o)
+
+        for i in range(1, 10):
+            logg.debug('execute time travel to period {}'.format(i))
+            self.backend.time_travel(self.start_time + (self.period_seconds * i))
+            (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+            self.rpc.do(o)
+            o = receipt(tx_hash)
+            r = self.rpc.do(o)
+            self.assertEqual(r['status'], 1)
+
+            o = c.redistributions(self.address, i, sender_address=self.accounts[0])
+            redistribution = self.rpc.do(o)
+
+            o = c.to_redistribution_demurrage_modifier(self.address, redistribution, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            demurrage = c.parse_to_redistribution_item(r)
+
+            o = c.redistributions(self.address, i-1, sender_address=self.accounts[0])
+            redistribution = self.rpc.do(o)
+
+            o = c.to_redistribution_demurrage_modifier(self.address, redistribution, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            demurrage_previous = c.parse_to_redistribution_item(r)
+
+            o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            balance_sink = c.parse_balance(r)
+
+            o = c.balance_of(self.address, self.accounts[0], sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            balance_minter = c.parse_balance(r)
+
+            logg.debug('testing sink {} mint {} adds up to supply {} with demurrage between {} and {}'.format(balance_sink, balance_minter, supply, demurrage_previous, demurrage))
+
+            self.assert_within_lower(balance_minter + balance_sink, supply, 0.001)
+
+
+    def test_redistribution_catchup_periods(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        demurrage = (1 - (self.tax_level / 1000000)) * (10**28)
+        supply = self.default_supply
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[0], supply)
+        self.rpc.do(o)
+
+        self.backend.time_travel(self.start_time + (self.period_seconds * 100))
+
+        balance_minter = None
+        balance_sink = None
+        real_supply = None
+
+        for i in range(1, 101):
+            (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+            self.rpc.do(o)
+            o = receipt(tx_hash)
+            r = self.rpc.do(o)
+            self.assertEqual(r['status'], 1)
+
+            o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            balance_sink = c.parse_balance(r)
+
+            o = c.balance_of(self.address, self.accounts[0], sender_address=self.accounts[0])
+            r = self.rpc.do(o)
+            balance_minter = c.parse_balance(r)
+            
+            real_supply = balance_sink + balance_minter
+            logg.info('period {} testing sink {} mint {} adds up to supply {} of original {} (delta {})'.format(i, balance_sink, balance_minter, real_supply, supply, supply - real_supply))
+
+        i = 100
+        o = c.redistributions(self.address, i, sender_address=self.accounts[0])
+        redistribution = self.rpc.do(o)
+
+        o = c.to_redistribution_demurrage_modifier(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage = c.parse_to_redistribution_item(r)
+
+        o = c.redistributions(self.address, i-1, sender_address=self.accounts[0])
+        redistribution = self.rpc.do(o)
+
+        o = c.to_redistribution_demurrage_modifier(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_previous = c.parse_to_redistribution_item(r)
+
+        o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance_sink = c.parse_balance(r)
+
+        o = c.balance_of(self.address, self.accounts[0], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance_minter = c.parse_balance(r)
+
+        logg.debug('testing sink {} mint {} adds up to supply {} with demurrage between {} and {}'.format(balance_sink, balance_minter, real_supply, demurrage_previous, demurrage))
+
+        self.assert_within_lower(balance_minter + balance_sink, supply, 0.001)
+
+
+#    def test_redistribution_boundaries(self):
+#        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+#        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+#
+#        demurrage = (1 - (self.tax_level / 1000000)) * (10**28)
+#        supply = self.default_supply
+#
+#        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[0], supply)
+#        self.rpc.do(o)
+#
+#        o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+#        r = self.rpc.do(o)
+#        balance = c.parse_balance(r)
+#        logg.debug('balance before {} supply {}'.format(balance, supply))
+#
+#        self.backend.time_travel(self.start_time + self.period_seconds)
+#        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+#        r = self.rpc.do(o)
+#
+#        o = receipt(tx_hash)
+#        r = self.rpc.do(o)
+#        self.assertEqual(r['status'], 1)
+#
+#        o = c.redistributions(self.address, 1, sender_address=self.accounts[0])
+#        r = self.rpc.do(o)
+#        oo = c.to_redistribution_supply(self.address, r, sender_address=self.accounts[0])
+#        rr = self.rpc.do(oo)
+#        oo = c.to_redistribution_demurrage_modifier(self.address, r, sender_address=self.accounts[0])
+#        rr = self.rpc.do(oo)
+#
+#        o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+#        r = self.rpc.do(o)
+#        balance = c.parse_balance(r)
+#
+#        self.backend.time_travel(self.start_time + self.period_seconds * 2 + 1)
+#        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+#        r = self.rpc.do(o)
+#
+#        o = receipt(tx_hash)
+#        r = self.rpc.do(o)
+#        self.assertEqual(r['status'], 1)
+#
+#        o = c.redistributions(self.address, 2, sender_address=self.accounts[0])
+#        r = self.rpc.do(o)
+#        oo = c.to_redistribution_supply(self.address, r, sender_address=self.accounts[0])
+#        rr = self.rpc.do(oo)
+#        oo = c.to_redistribution_demurrage_modifier(self.address, r, sender_address=self.accounts[0])
+#        rr = self.rpc.do(oo)
+#
+#        o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+#        r = self.rpc.do(o)
+#        balance = c.parse_balance(r)
+
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_redistribution_unit.py

@@ -21,7 +21,7 @@ from hexathon import (
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageUnit
+from erc20_demurrage_token.unittest.base import TestDemurrageUnit
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
@@ -31,12 +31,12 @@ testdir = os.path.dirname(__file__)
 
 class TestRedistribution(TestDemurrageUnit):
 
+
     # TODO: move to "pure" test file when getdistribution is implemented in all contracts
-    def test_distribution(self):
+    def test_distribution_direct(self):
         nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-        #demurrage = (1 - (self.tax_level / 1000000)) * (10**38)
         demurrage = (1 - (self.tax_level / 1000000)) * (10**28)
         supply = self.default_supply
 
@@ -51,21 +51,23 @@ class TestRedistribution(TestDemurrageUnit):
         nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-        #demurrage = (1 - (self.tax_level / 1000000)) * (10**38)
-        demurrage = (1 - (self.tax_level / 1000000)) * (10**28)
+        demurrage = (1 - (self.tax_level / 100000)) * (10**28)
+
+        logg.debug('demurrage {}'.format(demurrage))
         supply = self.default_supply
 
-        o = c.to_redistribution(self.address, 0, demurrage, supply, 1, sender_address=self.accounts[0])
+        o = c.to_redistribution(self.address, 0, demurrage, supply, 2, sender_address=self.accounts[0])
         redistribution = self.rpc.do(o)
 
         o = c.get_distribution_from_redistribution(self.address, redistribution, self.accounts[0])
         r = self.rpc.do(o)
         distribution = c.parse_get_distribution(r)
-        expected_distribution = self.default_supply * (self.tax_level / 1000000)
+        expected_distribution = (self.default_supply * self.tax_level) / 100000
+        logg.debug('distribution {} supply {}'.format(distribution, self.default_supply))
         self.assert_within_lower(distribution, expected_distribution, 1000)
 
 
-    def test_single_step(self):
+    def test_single_step_basic(self):
         nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
         c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
@@ -81,6 +83,12 @@ class TestRedistribution(TestDemurrageUnit):
 
         expected_balance = int(mint_amount - ((self.tax_level / 1000000) * mint_amount))
 
+        o = c.balance_of(self.address, ZERO_ADDRESS, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance(r)
+
+        logg.debug('balance {}'.format(balance))
+
         o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
         r = self.rpc.do(o)
         balance = c.parse_balance(r)
@@ -175,9 +183,6 @@ class TestRedistribution(TestDemurrageUnit):
         o = c.to_redistribution_demurrage_modifier(self.address, redistribution, sender_address=self.accounts[0])
         r = self.rpc.do(o)
         demurrage = c.parse_to_redistribution_item(r)
-#        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
-#        r = self.rpc.do(o)
-#        demurrage = c.parse_demurrage_amount(r)
         logg.debug('\nrediistribution {}\ndemurrage {}\nsupply {}'.format(redistribution, demurrage, supply))
 
         expected_balance = int(supply * (self.tax_level / 1000000))

python/tests/test_remainder.py

@@ -16,7 +16,7 @@ import eth_tester
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageDefault
+from erc20_demurrage_token.unittest.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()

python/tests/test_single.py

@@ -18,7 +18,7 @@ from hexathon import (
 from erc20_demurrage_token import DemurrageToken
 
 # test imports
-from tests.base import TestDemurrageSingle
+from erc20_demurrage_token.unittest.base import TestDemurrageSingle
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()

solidity/DemurrageTokenMultiCap.sol

@@ -61,6 +61,9 @@ contract DemurrageTokenMultiCap {
 	// (this constant x 1000000 is contained within 128 bits)
 	uint256 constant ppmDivider = 100000000000000000000000000000000;
 
+	// demurrage decimal width; 38 places
+	uint256 public immutable resolutionFactor = ppmDivider * 1000000;
+
 	// Timestamp of start of periods (time which contract constructor was called)
 	uint256 public immutable periodStart;
 

solidity/DemurrageTokenMultiNocap.sol

@@ -56,6 +56,9 @@ contract DemurrageTokenMultiNocap {
 	// (this constant x 1000000 is contained within 128 bits)
 	uint256 constant ppmDivider = 100000000000000000000000000000000;
 
+	// demurrage decimal width; 38 places
+	uint256 public immutable resolutionFactor = ppmDivider * 1000000;
+
 	// Timestamp of start of periods (time which contract constructor was called)
 	uint256 public immutable periodStart;
 

solidity/DemurrageTokenSingleCap.sol

@@ -56,7 +56,7 @@ contract DemurrageTokenSingleCap {
 	uint256 constant growthResolutionFactor = 1000000000000;
 
 	// demurrage decimal width; 38 places
-	uint256 immutable resolutionFactor = nanoDivider * growthResolutionFactor; 
+	uint256 public immutable resolutionFactor = nanoDivider * growthResolutionFactor; 
 
 	// Timestamp of start of periods (time which contract constructor was called)
 	uint256 public immutable periodStart;
@@ -128,6 +128,12 @@ contract DemurrageTokenSingleCap {
 		minimumParticipantSpend = 10 ** uint256(_decimals);
 	}
 
+	// Change sink address for redistribution
+	function setSinkAddress(address _sinkAddress) public {
+		require(msg.sender == owner);
+		sinkAddress = _sinkAddress;
+	}
+
 	// Given address will be allowed to call the mintTo() function
 	function addMinter(address _minter) public returns (bool) {
 		require(msg.sender == owner);
@@ -311,6 +317,10 @@ contract DemurrageTokenSingleCap {
 
 	// Calculate and cache the demurrage value corresponding to the (period of the) time of the method call
 	function applyDemurrage() public returns (bool) {
+		return applyDemurrageLimited(0);
+	}
+
+	function applyDemurrageLimited(uint256 _rounds) public returns (bool) {
 		//uint128 epochPeriodCount;
 		uint256 periodCount;
 		uint256 lastDemurrageAmount;
@@ -323,6 +333,12 @@ contract DemurrageTokenSingleCap {
 			return false;
 		}
 		lastDemurrageAmount = demurrageAmount;
+		// safety limit for exponential calculation to ensure that we can always
+		// execute this code no matter how much time passes.			
+		if (_rounds > 0 && _rounds < periodCount) {
+			periodCount = _rounds;
+		}
+
 		demurrageAmount = uint128(decayBy(lastDemurrageAmount, periodCount));
 		//demurragePeriod = epochPeriodCount; 
 		demurrageTimestamp = demurrageTimestamp + (periodCount * 60);

solidity/DemurrageTokenSingleNocap.sol

@@ -1,7 +1,6 @@
-pragma solidity > 0.6.11;
+pragma solidity >= 0.8.0;
 
 // SPDX-License-Identifier: GPL-3.0-or-later
-
 contract DemurrageTokenSingleCap {
 
 	// Redistribution bit field, with associated shifts and masks
@@ -12,16 +11,20 @@ contract DemurrageTokenSingleCap {
 	uint8 constant shiftRedistributionValue 	= 32;
 	uint256 constant maskRedistributionValue	= 0x00000000000000000000000000000000000000ffffffffffffffffff00000000; // ((1 << 72) - 1) << 32
 	uint8 constant shiftRedistributionDemurrage	= 104;
-	uint256 constant maskRedistributionDemurrage	= 0x0000000000ffffffffffffffffffffffffffff00000000000000000000000000; // ((1 << 20) - 1) << 140
+	uint256 constant maskRedistributionDemurrage	= 0x0000000000ffffffffffffffffffffffffffff00000000000000000000000000; // ((1 << 36) - 1) << 140
 
 	// Account balances
-	mapping (address => uint256) account;
+	mapping (address => bytes32[] ) account;
+	uint8 constant shiftAccountValue		= 0;
+	uint256 constant maskAccountValue 		= 0x0000000000000000000000000000000000000000000000ffffffffffffffffff; // (1 << 72) - 1
+	uint8 constant shiftAccountPeriod		= 72;
+	uint256 constant maskAccountPeriod 		= 0x00000000000000000000000000000000000000ffffffff000000000000000000; // ((1 << 32) - 1) << 72
+	uint8 constant shiftAccountUsed			= 255;
+	uint256 constant maskAccountUsed 		= 0x8000000000000000000000000000000000000000000000000000000000000000; // (1 << 255)
 	
 	// Cached demurrage amount, ppm with 38 digit resolution
 	uint128 public demurrageAmount;
 
-	// Cached demurrage period; the period for which demurrageAmount was calculated
-	//uint128 public demurragePeriod;
 	// Cached demurrage timestamp; the timestamp for which demurrageAmount was last calculated
 	uint256 public demurrageTimestamp;
 
@@ -40,10 +43,17 @@ contract DemurrageTokenSingleCap {
 	uint256 public decimals;
 
 	// Implements ERC20
-	uint256 public totalSupply;
+	//uint256 public totalSupply;
+	uint256 supply;
 
-	// Minimum amount of (demurraged) tokens an account must spend to participate in redistribution for a particular period
-	uint256 public minimumParticipantSpend;
+	// Last executed period
+	uint256 public lastPeriod;
+
+	// Last sink redistribution amount
+	uint256 public totalSink;
+
+	// Value of burnt tokens (burnt tokens do not decay)
+	uint256 public burned;
 
 	// 128 bit resolution of the demurrage divisor
 	// (this constant x 1000000 is contained within 128 bits)
@@ -53,7 +63,7 @@ contract DemurrageTokenSingleCap {
 	uint256 constant growthResolutionFactor = 1000000000000;
 
 	// demurrage decimal width; 38 places
-	uint256 immutable resolutionFactor = nanoDivider * growthResolutionFactor; 
+	uint256 public immutable resolutionFactor = nanoDivider * growthResolutionFactor; 
 
 	// Timestamp of start of periods (time which contract constructor was called)
 	uint256 public immutable periodStart;
@@ -71,7 +81,7 @@ contract DemurrageTokenSingleCap {
 	mapping (address => mapping (address => uint256 ) ) allowance; // holder -> spender -> amount (amount is subject to demurrage)
 
 	// Address to send unallocated redistribution tokens
-	address sinkAddress; 
+	address public sinkAddress; 
 
 	// Implements ERC20
 	event Transfer(address indexed _from, address indexed _to, uint256 _value);
@@ -94,6 +104,9 @@ contract DemurrageTokenSingleCap {
 	// Temporary event used in development, will be removed on prod
 	event Debug(bytes32 _foo);
 
+	// Emitted when tokens are burned
+	event Burn(address indexed _burner, uint256 _value);
+
 	// EIP173
 	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); // EIP173
 
@@ -111,17 +124,20 @@ contract DemurrageTokenSingleCap {
 		demurrageTimestamp = block.timestamp;
 		periodStart = demurrageTimestamp;
 		periodDuration = _periodMinutes * 60;
-		//demurrageAmount = 100000000000000000000000000000000000000 - _taxLevelMinute; // Represents 38 decimal places, same as resolutionFactor
-		//demurrageAmount = 100000000000000000000000000000000000000;
-		demurrageAmount = 10000000000000000000000000000;
-		//demurragePeriod = 1;
+		demurrageAmount = uint128(nanoDivider) * 100;
 		taxLevel = _taxLevelMinute; // Represents 38 decimal places
 		bytes32 initialRedistribution = toRedistribution(0, demurrageAmount, 0, 1);
 		redistributions.push(initialRedistribution);
 
 		// Misc settings
 		sinkAddress = _defaultSinkAddress;
-		minimumParticipantSpend = 10 ** uint256(_decimals);
+	}
+
+
+	// Change sink address for redistribution
+	function setSinkAddress(address _sinkAddress) public {
+		require(msg.sender == owner);
+		sinkAddress = _sinkAddress;
 	}
 
 	// Given address will be allowed to call the mintTo() function
@@ -146,52 +162,43 @@ contract DemurrageTokenSingleCap {
 
 		baseBalance = baseBalanceOf(_account);
 
-		//periodCount = actualPeriod() - demurragePeriod; 
 		periodCount = getMinutesDelta(demurrageTimestamp);
 
-		//currentDemurragedAmount = uint128(decayBy(demurrageAmount, periodCount));
 		currentDemurragedAmount = uint128(decayBy(demurrageAmount * 10000000000, periodCount));
 
 		return (baseBalance * currentDemurragedAmount) / (nanoDivider * 1000000000000);
 	}
 
+
 	/// Balance unmodified by demurrage
 	function baseBalanceOf(address _account) public view returns (uint256) {
-		return account[_account];
+		uint256 lastPeriodUsed;
+
+		lastPeriodUsed = account[_account].length;
+		if (lastPeriodUsed == 0) {
+			return 0;
+		}
+		return uint256(account[_account][lastPeriodUsed]) & maskAccountValue;
 	}
 
+
 	/// Increases base balance for a single account
 	function increaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
-		uint256 oldBalance;
-		uint256 newBalance;
-		uint256 workAccount;
-
-		workAccount = uint256(account[_account]);
-	
 		if (_delta == 0) {
 			return false;
 		}
-
-		oldBalance = baseBalanceOf(_account);
-		account[_account] = oldBalance + _delta;
+		
+		movePeriodBalance(_account, int256(_delta));
 		return true;
 	}
 
 	/// Decreases base balance for a single account
 	function decreaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
-		uint256 oldBalance;
-	       	uint256 newBalance;
-		uint256 workAccount;
-
-		workAccount = uint256(account[_account]);
-
 		if (_delta == 0) {
 			return false;
 		}
 
-		oldBalance = baseBalanceOf(_account);	
-		require(oldBalance >= _delta, 'ERR_OVERSPEND'); // overspend guard
-		account[_account] = oldBalance - _delta;
+		movePeriodBalance(_account, int256(_delta) * -1);
 		return true;
 	}
 
@@ -204,7 +211,7 @@ contract DemurrageTokenSingleCap {
 
 		changePeriod();
 		baseAmount = toBaseAmount(_amount);
-		totalSupply += _amount;
+		supply += _amount;
 		increaseBaseBalance(_beneficiary, baseAmount);
 		emit Mint(msg.sender, _beneficiary, _amount);
 		saveRedistributionSupply();
@@ -247,8 +254,7 @@ contract DemurrageTokenSingleCap {
 		uint256 currentRedistribution;
 		uint256 grownSupply;
 
-		//grownSupply = growBy(totalSupply, 1);
-		grownSupply = totalSupply;
+		grownSupply = totalSupply();
 		currentRedistribution = uint256(redistributions[redistributions.length-1]);
 		currentRedistribution &= (~maskRedistributionValue);
 		currentRedistribution |= (grownSupply << shiftRedistributionValue);
@@ -262,12 +268,12 @@ contract DemurrageTokenSingleCap {
 		return uint128((block.timestamp - periodStart) / periodDuration + 1);
 	}
 
-	// Add an entered demurrage period to the redistribution array
+	// Retrieve next redistribution if the period threshold has been crossed
 	function checkPeriod() private view returns (bytes32) {
 		bytes32 lastRedistribution;
 		uint256 currentPeriod;
 
-		lastRedistribution =  redistributions[redistributions.length-1];
+		lastRedistribution =  redistributions[lastPeriod];
 		currentPeriod = this.actualPeriod();
 		if (currentPeriod <= toRedistributionPeriod(lastRedistribution)) {
 			return bytes32(0x00);
@@ -278,7 +284,7 @@ contract DemurrageTokenSingleCap {
 	function getDistribution(uint256 _supply, uint256 _demurrageAmount) public view returns (uint256) {
 		uint256 difference;
 
-		difference = _supply * (resolutionFactor - _demurrageAmount); //(nanoDivider - ((resolutionFactor - _demurrageAmount) / nanoDivider));
+		difference = _supply * (resolutionFactor - (_demurrageAmount * 10000000000));
 		return difference / resolutionFactor;
 	}
 
@@ -294,9 +300,13 @@ contract DemurrageTokenSingleCap {
 	// Returns the amount sent to the sink address
 	function applyDefaultRedistribution(bytes32 _redistribution) private returns (uint256) {
 		uint256 unit;
+		uint256 baseUnit;
 	
 		unit = getDistributionFromRedistribution(_redistribution);	
-		increaseBaseBalance(sinkAddress, toBaseAmount(unit));
+		baseUnit = toBaseAmount(unit) - totalSink;
+		increaseBaseBalance(sinkAddress, baseUnit);
+		lastPeriod += 1;
+		totalSink += baseUnit;
 		return unit;
 	}
 
@@ -307,18 +317,25 @@ contract DemurrageTokenSingleCap {
 
 	// Calculate and cache the demurrage value corresponding to the (period of the) time of the method call
 	function applyDemurrage() public returns (bool) {
-		//uint128 epochPeriodCount;
+		return applyDemurrageLimited(0);
+	}
+
+	function applyDemurrageLimited(uint256 _rounds) public returns (bool) {
 		uint256 periodCount;
 		uint256 lastDemurrageAmount;
 
-		//epochPeriodCount = actualPeriod();
-		//periodCount = epochPeriodCount - demurragePeriod;
-
 		periodCount = getMinutesDelta(demurrageTimestamp);
 		if (periodCount == 0) {
 			return false;
 		}
 		lastDemurrageAmount = demurrageAmount;
+	
+		// safety limit for exponential calculation to ensure that we can always
+		// execute this code no matter how much time passes.			
+		if (_rounds > 0 && _rounds < periodCount) {
+			periodCount = _rounds;
+		}
+
 		demurrageAmount = uint128(decayBy(lastDemurrageAmount, periodCount));
 		//demurragePeriod = epochPeriodCount; 
 		demurrageTimestamp = demurrageTimestamp + (periodCount * 60);
@@ -336,15 +353,64 @@ contract DemurrageTokenSingleCap {
 		return (block.timestamp - _target) / 60;
 	}
 
+
+	// Deserialize the pemurrage period for the given account is participating in
+	function accountPeriod(address _account) public view returns (uint256) {
+		uint256 accountPeriods;
+
+		accountPeriods = account[_account].length;
+		if (accountPeriods == 0) {
+			return 0;
+		}
+		return accountPeriodBase(_account, accountPeriods - 1);
+	}
+
+	function accountPeriodBase(address _account, uint256 _idx) private view returns (uint256) {
+		return (uint256(account[_account][_idx]) & maskAccountPeriod) >> shiftAccountPeriod;
+	}
+
+	function movePeriodBalance(address _account, int256 _delta) private {
+		int256 oldBalance;
+		uint256 newBalance;
+		uint256 workAccount;
+
+		//workAccount = uint256(account[_index][_account]);
+
+		oldBalance = int256(baseBalanceOf(_account));
+		newBalance = uint256(oldBalance + _delta);
+		require(uint72(newBalance) > uint72(uint256(oldBalance)), 'ERR_WOULDWRAP'); // revert if increase would result in a wrapped value
+		workAccount = (1 << 255);
+
+		workAccount |= ((uint32(lastPeriod) << shiftAccountPeriod) & maskAccountPeriod);
+		workAccount |= (baseBalanceOf(_account) & maskAccountValue);
+		account[_account].push(bytes32(workAccount));
+	}
+
+	function registerAccountPeriod(address _account, int256 _delta) public {
+		uint256 accountPeriods;
+		uint256 lastPeriodUsed;
+
+		accountPeriods = account[_account].length;
+		if (lastPeriodUsed == 0) {
+			account[_account].push(bytes32(uint256(_delta) | (1 << 255)));
+			return;
+		}
+		lastPeriodUsed = accountPeriodBase(_account, accountPeriods - 1);
+		if (lastPeriodUsed != lastPeriod) {
+			movePeriodBalance(_account, _delta);
+		}
+	}
+
 	// Recalculate the demurrage modifier for the new period
+	// Note that the supply for the consecutive period will be taken at the time of code execution, and thus not necessarily at the time when the redistribution period threshold was crossed.
 	function changePeriod() public returns (bool) {
 		bytes32 currentRedistribution;
 		bytes32 nextRedistribution;
 		uint256 currentPeriod;
-		uint256 currentDemurrageAmount;
+		uint256 lastDemurrageAmount;
+		bytes32 lastRedistribution;
 		uint256 nextRedistributionDemurrage;
 		uint256 demurrageCounts;
-		uint256 periodTimestamp;
 		uint256 nextPeriod;
 
 		applyDemurrage();
@@ -353,20 +419,15 @@ contract DemurrageTokenSingleCap {
 			return false;
 		}
 
+		// calculate the decay from previous redistributino
+		lastRedistribution = redistributions[lastPeriod];
 		currentPeriod = toRedistributionPeriod(currentRedistribution);
 		nextPeriod = currentPeriod + 1;
-		periodTimestamp = getPeriodTimeDelta(currentPeriod);
-
-		currentDemurrageAmount = demurrageAmount; 
-
-		demurrageCounts = demurrageCycles(periodTimestamp);
-		if (demurrageCounts > 0) {
-			nextRedistributionDemurrage = growBy(currentDemurrageAmount, demurrageCounts);
-		} else {
-			nextRedistributionDemurrage = currentDemurrageAmount;
-		}
-		
-		nextRedistribution = toRedistribution(0, nextRedistributionDemurrage, totalSupply, nextPeriod);
+		lastDemurrageAmount = toRedistributionDemurrageModifier(lastRedistribution);
+		demurrageCounts = periodDuration / 60;
+		nextRedistributionDemurrage = decayBy(lastDemurrageAmount, demurrageCounts);
+	
+		nextRedistribution = toRedistribution(0, nextRedistributionDemurrage, totalSupply(), nextPeriod);
 		redistributions.push(nextRedistribution);
 
 		applyDefaultRedistribution(nextRedistribution);
@@ -404,7 +465,6 @@ contract DemurrageTokenSingleCap {
 
 	// Inflates the given amount according to the current demurrage modifier
 	function toBaseAmount(uint256 _value) public view returns (uint256) {
-		//return (_value * resolutionFactor) / demurrageAmount;
 		return (_value * resolutionFactor) / (demurrageAmount * 10000000000);
 	}
 
@@ -412,14 +472,45 @@ contract DemurrageTokenSingleCap {
 	function approve(address _spender, uint256 _value) public returns (bool) {
 		uint256 baseValue;
 
+		if (allowance[msg.sender][_spender] > 0) {
+			require(_value == 0, 'ZERO_FIRST');
+		}
+		
 		changePeriod();
 
 		baseValue = toBaseAmount(_value);
-		allowance[msg.sender][_spender] += baseValue;
+		allowance[msg.sender][_spender] = baseValue;
 		emit Approval(msg.sender, _spender, _value);
 		return true;
 	}
 
+	// Reduce allowance by amount
+	function decreaseAllowance(address _spender, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+
+		baseValue = toBaseAmount(_value);
+		require(allowance[msg.sender][_spender] >= baseValue);
+		
+		changePeriod();
+
+		allowance[msg.sender][_spender] -= baseValue;
+		emit Approval(msg.sender, _spender, allowance[msg.sender][_spender]);
+		return true;
+	}
+
+	// Increase allowance by amount
+	function increaseAllowance(address _spender, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+
+		allowance[msg.sender][_spender] += baseValue;
+		emit Approval(msg.sender, _spender, allowance[msg.sender][_spender]);
+		return true;
+	}
+
 	// Implements ERC20, triggers tax and/or redistribution
 	function transfer(address _to, uint256 _value) public returns (bool) {
 		uint256 baseValue;
@@ -443,7 +534,9 @@ contract DemurrageTokenSingleCap {
 		baseValue = toBaseAmount(_value);
 		require(allowance[_from][msg.sender] >= baseValue);
 
+		allowance[_from][msg.sender] -= baseValue;
 		result = transferBase(_from, _to, baseValue);
+
 		emit Transfer(_from, _to, _value);
 		return result;
 	}
@@ -455,7 +548,6 @@ contract DemurrageTokenSingleCap {
 		decreaseBaseBalance(_from, _value);
 		increaseBaseBalance(_to, _value);
 
-		//period = actualPeriod();
 		return true;
 	}
 
@@ -476,6 +568,29 @@ contract DemurrageTokenSingleCap {
 		emit OwnershipTransferred(oldOwner, owner);
 	}
 
+	// Explicitly and irretrievably burn tokens
+	// Only token minters can burn tokens
+	function burn(uint256 _value) public {
+		require(minter[msg.sender]);
+		require(_value <= balanceOf(msg.sender));
+		uint256 _delta = toBaseAmount(_value);
+
+		applyDemurrage();
+		decreaseBaseBalance(msg.sender, _delta);
+		burned += _value;
+		emit Burn(msg.sender, _value);
+	}
+
+	// Implements ERC20
+	function totalSupply() public view returns (uint256) {
+		return supply - burned;
+	}
+
+	// Return total number of burned tokens
+	function totalBurned() public view returns (uint256) {
+		return burned;
+	}
+
 	// Implements EIP165
 	function supportsInterface(bytes4 _sum) public pure returns (bool) {
 		if (_sum == 0xc6bb4b70) { // ERC20

solidity/Makefile

@@ -33,6 +33,10 @@ test: all
 	python ../python/tests/test_pure.py
 
 install: all
+	#cp -v DemurrageToken*.{json,bin} ../python/erc20_demurrage_token/data/
+	cp -v DemurrageTokenSingleNocap.{json,bin} ../python/erc20_demurrage_token/data/
+
+install-broken: all
 	cp -v DemurrageToken*.{json,bin} ../python/erc20_demurrage_token/data/
 	
 .PHONY: test install