diff --git a/src/block.rs b/src/block.rs
index 963124be0..f8e8ef16f 100644
--- a/src/block.rs
+++ b/src/block.rs
@@ -349,38 +349,49 @@ pub fn enact_and_seal(block_bytes: &[u8], engine: &Engine, db: JournalDB, parent
 	Ok(try!(try!(enact_bytes(block_bytes, engine, db, parent, last_hashes)).seal(header.seal())))
 }
 
-#[test]
-fn open_block() {
-	use spec::*;
-	let engine = Spec::new_test().to_engine().unwrap();
-	let genesis_header = engine.spec().genesis_header();
-	let mut db = JournalDB::new_temp();
-	engine.spec().ensure_db_good(&mut db);
-	let last_hashes = vec![genesis_header.hash()];
-	let b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
-	let b = b.close();
-	let _ = b.seal(vec![]);
-}
+#[cfg(test)]
+mod tests {
+	use tests::helpers::*;
+	use super::*;
+	use common::*;
+	use engine::*;
 
-#[test]
-fn enact_block() {
-	use spec::*;
-	let engine = Spec::new_test().to_engine().unwrap();
-	let genesis_header = engine.spec().genesis_header();
+	#[test]
+	fn open_block() {
+		use spec::*;
+		let engine = Spec::new_test().to_engine().unwrap();
+		let genesis_header = engine.spec().genesis_header();
+		let mut db_result = get_temp_journal_db();
+		let db = db_result.reference_mut();
+		engine.spec().ensure_db_good(db);
+		let last_hashes = vec![genesis_header.hash()];
+		let b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &last_hashes, Address::zero(), vec![]);
+		let b = b.close();
+		let _ = b.seal(vec![]);
+	}
 
-	let mut db = JournalDB::new_temp();
-	engine.spec().ensure_db_good(&mut db);
-	let b = OpenBlock::new(engine.deref(), db, &genesis_header, &vec![genesis_header.hash()], Address::zero(), vec![]).close().seal(vec![]).unwrap();
-	let orig_bytes = b.rlp_bytes();
-	let orig_db = b.drain();
+	#[test]
+	fn enact_block() {
+		use spec::*;
+		let engine = Spec::new_test().to_engine().unwrap();
+		let genesis_header = engine.spec().genesis_header();
 
-	let mut db = JournalDB::new_temp();
-	engine.spec().ensure_db_good(&mut db);
-	let e = enact_and_seal(&orig_bytes, engine.deref(), db, &genesis_header, &vec![genesis_header.hash()]).unwrap();
+		let mut db_result = get_temp_journal_db();
+		let db = db_result.reference_mut();
+		engine.spec().ensure_db_good(db);
+		let b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &vec![genesis_header.hash()], Address::zero(), vec![]).close().seal(vec![]).unwrap();
+		let orig_bytes = b.rlp_bytes();
+		let orig_db = b.drain();
 
-	assert_eq!(e.rlp_bytes(), orig_bytes);
-	
-	let db = e.drain();
-	assert_eq!(orig_db.keys(), db.keys());
-	assert!(orig_db.keys().iter().filter(|k| orig_db.get(k.0) != db.get(k.0)).next() == None);
-}
+		let mut db_result = get_temp_journal_db();
+		let db = db_result.reference_mut();
+		engine.spec().ensure_db_good(db);
+		let e = enact_and_seal(&orig_bytes, engine.deref(), db.clone(), &genesis_header, &vec![genesis_header.hash()]).unwrap();
+
+		assert_eq!(e.rlp_bytes(), orig_bytes);
+
+		let db = e.drain();
+		assert_eq!(orig_db.keys(), db.keys());
+		assert!(orig_db.keys().iter().filter(|k| orig_db.get(k.0) != db.get(k.0)).next() == None);
+	}
+}
\ No newline at end of file
diff --git a/src/ethereum/ethash.rs b/src/ethereum/ethash.rs
index f28ea31c6..ce40c5f42 100644
--- a/src/ethereum/ethash.rs
+++ b/src/ethereum/ethash.rs
@@ -7,6 +7,8 @@ use spec::*;
 use engine::*;
 use evm::Schedule;
 use evm::Factory;
+#[cfg(test)]
+use tests::helpers::*;
 
 /// Engine using Ethash proof-of-work consensus algorithm, suitable for Ethereum
 /// mainnet chains in the Olympic, Frontier and Homestead eras.
@@ -227,10 +229,11 @@ fn on_close_block() {
 	use super::*;
 	let engine = new_morden().to_engine().unwrap();
 	let genesis_header = engine.spec().genesis_header();
-	let mut db = JournalDB::new_temp();
-	engine.spec().ensure_db_good(&mut db);
+	let mut db_result = get_temp_journal_db();
+	let mut db = db_result.reference_mut();
+	engine.spec().ensure_db_good(db);
 	let last_hashes = vec![genesis_header.hash()];
-	let b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
+	let b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &last_hashes, Address::zero(), vec![]);
 	let b = b.close();
 	assert_eq!(b.state().balance(&Address::zero()), U256::from_str("4563918244f40000").unwrap());
 }
@@ -240,10 +243,11 @@ fn on_close_block_with_uncle() {
 	use super::*;
 	let engine = new_morden().to_engine().unwrap();
 	let genesis_header = engine.spec().genesis_header();
-	let mut db = JournalDB::new_temp();
-	engine.spec().ensure_db_good(&mut db);
+	let mut db_result = get_temp_journal_db();
+	let mut db = db_result.reference_mut();
+	engine.spec().ensure_db_good(db);
 	let last_hashes = vec![genesis_header.hash()];
-	let mut b = OpenBlock::new(engine.deref(), db, &genesis_header, &last_hashes, Address::zero(), vec![]);
+	let mut b = OpenBlock::new(engine.deref(), db.clone(), &genesis_header, &last_hashes, Address::zero(), vec![]);
 	let mut uncle = Header::new();
 	let uncle_author = address_from_hex("ef2d6d194084c2de36e0dabfce45d046b37d1106");
 	uncle.author = uncle_author.clone();
diff --git a/src/ethereum/mod.rs b/src/ethereum/mod.rs
index 66bb7f356..5dd5a8da2 100644
--- a/src/ethereum/mod.rs
+++ b/src/ethereum/mod.rs
@@ -37,13 +37,15 @@ mod tests {
 	use state::*;
 	use engine::*;
 	use super::*;
+	use tests::helpers::*;
 
 	#[test]
 	fn ensure_db_good() {
 		let engine = new_morden().to_engine().unwrap();
 		let genesis_header = engine.spec().genesis_header();
-		let mut db = JournalDB::new_temp();
-		engine.spec().ensure_db_good(&mut db);
+		let mut db_result = get_temp_journal_db();
+		let mut db = db_result.reference_mut();
+		engine.spec().ensure_db_good(db);
 		let s = State::from_existing(db.clone(), genesis_header.state_root.clone(), engine.account_start_nonce());
 		assert_eq!(s.balance(&address_from_hex("0000000000000000000000000000000000000001")), U256::from(1u64));
 		assert_eq!(s.balance(&address_from_hex("0000000000000000000000000000000000000002")), U256::from(1u64));
diff --git a/src/executive.rs b/src/executive.rs
index b113363fd..5e1689830 100644
--- a/src/executive.rs
+++ b/src/executive.rs
@@ -341,12 +341,12 @@ impl<'a> Executive<'a> {
 mod tests {
 	use super::*;
 	use common::*;
-	use state::*;
 	use ethereum;
 	use engine::*;
 	use spec::*;
 	use evm::{Schedule, Factory, VMType};
 	use substate::*;
+	use tests::helpers::*;
 
 	struct TestEngine {
 		factory: Factory,
@@ -395,7 +395,8 @@ mod tests {
 		params.gas = U256::from(100_000);
 		params.code = Some("3331600055".from_hex().unwrap());
 		params.value = ActionValue::Transfer(U256::from(0x7));
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.add_balance(&sender, &U256::from(0x100u64));
 		let info = EnvInfo::new();
 		let engine = TestEngine::new(0, factory);
@@ -453,7 +454,8 @@ mod tests {
 		params.gas = U256::from(100_000);
 		params.code = Some(code.clone());
 		params.value = ActionValue::Transfer(U256::from(100));
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.add_balance(&sender, &U256::from(100));
 		let info = EnvInfo::new();
 		let engine = TestEngine::new(0, factory);
@@ -506,7 +508,8 @@ mod tests {
 		params.gas = U256::from(100_000);
 		params.code = Some(code.clone());
 		params.value = ActionValue::Transfer(U256::from(100));
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.add_balance(&sender, &U256::from(100));
 		let info = EnvInfo::new();
 		let engine = TestEngine::new(0, factory);
@@ -557,7 +560,8 @@ mod tests {
 		params.gas = U256::from(100_000);
 		params.code = Some(code.clone());
 		params.value = ActionValue::Transfer(U256::from(100));
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.add_balance(&sender, &U256::from(100));
 		let info = EnvInfo::new();
 		let engine = TestEngine::new(1024, factory);
@@ -613,7 +617,8 @@ mod tests {
 		params.code = Some(code_a.clone());
 		params.value = ActionValue::Transfer(U256::from(100_000));
 
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.init_code(&address_a, code_a.clone());
 		state.init_code(&address_b, code_b.clone());
 		state.add_balance(&sender, &U256::from(100_000));
@@ -659,7 +664,8 @@ mod tests {
 		params.address = address.clone();
 		params.gas = U256::from(100_000);
 		params.code = Some(code.clone());
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.init_code(&address, code.clone());
 		let info = EnvInfo::new();
 		let engine = TestEngine::new(0, factory);
@@ -684,8 +690,9 @@ mod tests {
 		let sender = t.sender().unwrap();
 		let contract = contract_address(&sender, &U256::zero());
 
-		let mut state = State::new_temp();
-		state.add_balance(&sender, &U256::from(18));	
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
+		state.add_balance(&sender, &U256::from(18));
 		let mut info = EnvInfo::new();
 		info.gas_limit = U256::from(100_000);
 		let engine = TestEngine::new(0, factory);
@@ -711,7 +718,8 @@ mod tests {
 	fn test_transact_invalid_sender(factory: Factory) {
 		let t = Transaction::new_create(U256::from(17), "3331600055".from_hex().unwrap(), U256::from(100_000), U256::zero(), U256::zero());
 
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		let mut info = EnvInfo::new();
 		info.gas_limit = U256::from(100_000);
 		let engine = TestEngine::new(0, factory);
@@ -734,8 +742,9 @@ mod tests {
 		t.sign(&keypair.secret());
 		let sender = t.sender().unwrap();
 		
-		let mut state = State::new_temp();
-		state.add_balance(&sender, &U256::from(17));	
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
+		state.add_balance(&sender, &U256::from(17));
 		let mut info = EnvInfo::new();
 		info.gas_limit = U256::from(100_000);
 		let engine = TestEngine::new(0, factory);
@@ -759,8 +768,9 @@ mod tests {
 		t.sign(&keypair.secret());
 		let sender = t.sender().unwrap();
 
-		let mut state = State::new_temp();
-		state.add_balance(&sender, &U256::from(17));	
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
+		state.add_balance(&sender, &U256::from(17));
 		let mut info = EnvInfo::new();
 		info.gas_used = U256::from(20_000);
 		info.gas_limit = U256::from(100_000);
@@ -785,8 +795,9 @@ mod tests {
 		t.sign(&keypair.secret());
 		let sender = t.sender().unwrap();
 
-		let mut state = State::new_temp();
-		state.add_balance(&sender, &U256::from(100_017));	
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
+		state.add_balance(&sender, &U256::from(100_017));
 		let mut info = EnvInfo::new();
 		info.gas_limit = U256::from(100_000);
 		let engine = TestEngine::new(0, factory);
@@ -818,7 +829,8 @@ mod tests {
 		params.gas = U256::from(0x0186a0);
 		params.code = Some(code.clone());
 		params.value = ActionValue::Transfer(U256::from_str("0de0b6b3a7640000").unwrap());
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 		state.add_balance(&sender, &U256::from_str("152d02c7e14af6800000").unwrap());
 		let info = EnvInfo::new();
 		let engine = TestEngine::new(0, factory);
diff --git a/src/state.rs b/src/state.rs
index 7310f63a7..c1b7e71c6 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -50,11 +50,6 @@ impl State {
 		}
 	}
 
-	/// Create temporary state object
-	pub fn new_temp() -> State {
-		Self::new(JournalDB::new_temp(), U256::from(0u8))
-	}
-
 	/// Destroy the current object and return root and database.
 	pub fn drop(self) -> (H256, JournalDB) {
 		(self.root, self.db)
@@ -285,158 +280,169 @@ use util::trie::*;
 use util::rlp::*;
 use util::uint::*;
 use account::*;
+use tests::helpers::*;
 
 #[test]
 fn code_from_database() {
 	let a = Address::zero();
-	let (r, db) = {
-		let mut s = State::new_temp();
-		s.require_or_from(&a, false, ||Account::new_contract(U256::from(42u32)), |_|{});
-		s.init_code(&a, vec![1, 2, 3]);
-		assert_eq!(s.code(&a), Some([1u8, 2, 3].to_vec()));
-		s.commit();
-		assert_eq!(s.code(&a), Some([1u8, 2, 3].to_vec()));
-		s.drop()
+	let temp = RandomTempPath::new();
+	let (root, db) = {
+		let mut state = get_temp_state_in(temp.as_path());
+		state.require_or_from(&a, false, ||Account::new_contract(U256::from(42u32)), |_|{});
+		state.init_code(&a, vec![1, 2, 3]);
+		assert_eq!(state.code(&a), Some([1u8, 2, 3].to_vec()));
+		state.commit();
+		assert_eq!(state.code(&a), Some([1u8, 2, 3].to_vec()));
+		state.drop()
 	};
 
-	let s = State::from_existing(db, r, U256::from(0u8));
-	assert_eq!(s.code(&a), Some([1u8, 2, 3].to_vec()));
+	let state = State::from_existing(db, root, U256::from(0u8));
+	assert_eq!(state.code(&a), Some([1u8, 2, 3].to_vec()));
 }
 
 #[test]
 fn storage_at_from_database() {
 	let a = Address::zero();
-	let (r, db) = {
-		let mut s = State::new_temp();
-		s.set_storage(&a, H256::from(&U256::from(01u64)), H256::from(&U256::from(69u64)));
-		s.commit();
-		s.drop()
+	let temp = RandomTempPath::new();
+	let (root, db) = {
+		let mut state = get_temp_state_in(temp.as_path());
+		state.set_storage(&a, H256::from(&U256::from(01u64)), H256::from(&U256::from(69u64)));
+		state.commit();
+		state.drop()
 	};
 
-	let s = State::from_existing(db, r, U256::from(0u8));
+	let s = State::from_existing(db, root, U256::from(0u8));
 	assert_eq!(s.storage_at(&a, &H256::from(&U256::from(01u64))), H256::from(&U256::from(69u64)));
 }
 
 #[test]
 fn get_from_database() {
 	let a = Address::zero();
-	let (r, db) = {
-		let mut s = State::new_temp();
-		s.inc_nonce(&a);
-		s.add_balance(&a, &U256::from(69u64));
-		s.commit();
-		assert_eq!(s.balance(&a), U256::from(69u64));
-		s.drop()
+	let temp = RandomTempPath::new();
+	let (root, db) = {
+		let mut state = get_temp_state_in(temp.as_path());
+		state.inc_nonce(&a);
+		state.add_balance(&a, &U256::from(69u64));
+		state.commit();
+		assert_eq!(state.balance(&a), U256::from(69u64));
+		state.drop()
 	};
 
-	let s = State::from_existing(db, r, U256::from(0u8));
-	assert_eq!(s.balance(&a), U256::from(69u64));
-	assert_eq!(s.nonce(&a), U256::from(1u64));
+	let state = State::from_existing(db, root, U256::from(0u8));
+	assert_eq!(state.balance(&a), U256::from(69u64));
+	assert_eq!(state.nonce(&a), U256::from(1u64));
 }
 
 #[test]
 fn remove() {
 	let a = Address::zero();
-	let mut s = State::new_temp();
-	assert_eq!(s.exists(&a), false);
-	s.inc_nonce(&a);
-	assert_eq!(s.exists(&a), true);
-	assert_eq!(s.nonce(&a), U256::from(1u64));
-	s.kill_account(&a);
-	assert_eq!(s.exists(&a), false);
-	assert_eq!(s.nonce(&a), U256::from(0u64));
+	let mut state_result = get_temp_state();
+	let mut state = state_result.reference_mut();
+	assert_eq!(state.exists(&a), false);
+	state.inc_nonce(&a);
+	assert_eq!(state.exists(&a), true);
+	assert_eq!(state.nonce(&a), U256::from(1u64));
+	state.kill_account(&a);
+	assert_eq!(state.exists(&a), false);
+	assert_eq!(state.nonce(&a), U256::from(0u64));
 }
 
 #[test]
 fn remove_from_database() {
 	let a = Address::zero();
-	let (r, db) = {
-		let mut s = State::new_temp();
-		s.inc_nonce(&a);
-		s.commit();
-		assert_eq!(s.exists(&a), true);
-		assert_eq!(s.nonce(&a), U256::from(1u64));
-		s.drop()
+	let temp = RandomTempPath::new();
+	{
+		let mut state = get_temp_state_in(temp.as_path());
+		state.inc_nonce(&a);
+		state.commit();
+		assert_eq!(state.exists(&a), true);
+		assert_eq!(state.nonce(&a), U256::from(1u64));
+		state.drop()
 	};
 
-	let (r, db) = {
-		let mut s = State::from_existing(db, r, U256::from(0u8));
-		assert_eq!(s.exists(&a), true);
-		assert_eq!(s.nonce(&a), U256::from(1u64));
-		s.kill_account(&a);
-		s.commit();
-		assert_eq!(s.exists(&a), false);
-		assert_eq!(s.nonce(&a), U256::from(0u64));
-		s.drop()
+	let (root, db) = {
+		let mut state = get_temp_state_in(temp.as_path());
+		assert_eq!(state.exists(&a), true);
+		assert_eq!(state.nonce(&a), U256::from(1u64));
+		state.kill_account(&a);
+		state.commit();
+		assert_eq!(state.exists(&a), false);
+		assert_eq!(state.nonce(&a), U256::from(0u64));
+		state.drop()
 	};
 
-	let s = State::from_existing(db, r, U256::from(0u8));
-	assert_eq!(s.exists(&a), false);
-	assert_eq!(s.nonce(&a), U256::from(0u64));
+	let state = State::from_existing(db, root, U256::from(0u8));
+	assert_eq!(state.exists(&a), false);
+	assert_eq!(state.nonce(&a), U256::from(0u64));
 }
 
 #[test]
 fn alter_balance() {
-	let mut s = State::new_temp();
+	let mut state_result = get_temp_state();
+	let mut state = state_result.reference_mut();
 	let a = Address::zero();
 	let b = address_from_u64(1u64);
-	s.add_balance(&a, &U256::from(69u64));
-	assert_eq!(s.balance(&a), U256::from(69u64));
-	s.commit();
-	assert_eq!(s.balance(&a), U256::from(69u64));
-	s.sub_balance(&a, &U256::from(42u64));
-	assert_eq!(s.balance(&a), U256::from(27u64));
-	s.commit();
-	assert_eq!(s.balance(&a), U256::from(27u64));
-	s.transfer_balance(&a, &b, &U256::from(18u64));
-	assert_eq!(s.balance(&a), U256::from(9u64));
-	assert_eq!(s.balance(&b), U256::from(18u64));
-	s.commit();
-	assert_eq!(s.balance(&a), U256::from(9u64));
-	assert_eq!(s.balance(&b), U256::from(18u64));
+	state.add_balance(&a, &U256::from(69u64));
+	assert_eq!(state.balance(&a), U256::from(69u64));
+	state.commit();
+	assert_eq!(state.balance(&a), U256::from(69u64));
+	state.sub_balance(&a, &U256::from(42u64));
+	assert_eq!(state.balance(&a), U256::from(27u64));
+	state.commit();
+	assert_eq!(state.balance(&a), U256::from(27u64));
+	state.transfer_balance(&a, &b, &U256::from(18u64));
+	assert_eq!(state.balance(&a), U256::from(9u64));
+	assert_eq!(state.balance(&b), U256::from(18u64));
+	state.commit();
+	assert_eq!(state.balance(&a), U256::from(9u64));
+	assert_eq!(state.balance(&b), U256::from(18u64));
 }
 
 #[test]
 fn alter_nonce() {
-	let mut s = State::new_temp();
+	let mut state_result = get_temp_state();
+	let mut state = state_result.reference_mut();
 	let a = Address::zero();
-	s.inc_nonce(&a);
-	assert_eq!(s.nonce(&a), U256::from(1u64));
-	s.inc_nonce(&a);
-	assert_eq!(s.nonce(&a), U256::from(2u64));
-	s.commit();
-	assert_eq!(s.nonce(&a), U256::from(2u64));
-	s.inc_nonce(&a);
-	assert_eq!(s.nonce(&a), U256::from(3u64));
-	s.commit();
-	assert_eq!(s.nonce(&a), U256::from(3u64));
+	state.inc_nonce(&a);
+	assert_eq!(state.nonce(&a), U256::from(1u64));
+	state.inc_nonce(&a);
+	assert_eq!(state.nonce(&a), U256::from(2u64));
+	state.commit();
+	assert_eq!(state.nonce(&a), U256::from(2u64));
+	state.inc_nonce(&a);
+	assert_eq!(state.nonce(&a), U256::from(3u64));
+	state.commit();
+	assert_eq!(state.nonce(&a), U256::from(3u64));
 }
 
 #[test]
 fn balance_nonce() {
-	let mut s = State::new_temp();
+	let mut state_result = get_temp_state();
+	let mut state = state_result.reference_mut();
 	let a = Address::zero();
-	assert_eq!(s.balance(&a), U256::from(0u64));
-	assert_eq!(s.nonce(&a), U256::from(0u64));
-	s.commit();
-	assert_eq!(s.balance(&a), U256::from(0u64));
-	assert_eq!(s.nonce(&a), U256::from(0u64));
+	assert_eq!(state.balance(&a), U256::from(0u64));
+	assert_eq!(state.nonce(&a), U256::from(0u64));
+	state.commit();
+	assert_eq!(state.balance(&a), U256::from(0u64));
+	assert_eq!(state.nonce(&a), U256::from(0u64));
 }
 
 #[test]
 fn ensure_cached() {
-	let mut s = State::new_temp();
+	let mut state_result = get_temp_state();
+	let mut state = state_result.reference_mut();
 	let a = Address::zero();
-	s.require(&a, false);
-	s.commit();
-	assert_eq!(s.root().hex(), "0ce23f3c809de377b008a4a3ee94a0834aac8bec1f86e28ffe4fdb5a15b0c785");
+	state.require(&a, false);
+	state.commit();
+	assert_eq!(state.root().hex(), "0ce23f3c809de377b008a4a3ee94a0834aac8bec1f86e28ffe4fdb5a15b0c785");
 }
 
 #[test]
 fn create_empty() {
-	let mut s = State::new_temp();
-	s.commit();
-	assert_eq!(s.root().hex(), "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421");
+	let mut state_result = get_temp_state();
+	let mut state = state_result.reference_mut();
+	state.commit();
+	assert_eq!(state.root().hex(), "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421");
 }
 
 }
diff --git a/src/substate.rs b/src/substate.rs
index d2aca983e..e14ac4d20 100644
--- a/src/substate.rs
+++ b/src/substate.rs
@@ -37,11 +37,15 @@ impl Substate {
 #[cfg(test)]
 mod tests {
 	use super::*;
+	use util::hash::*;
 
 	#[test]
 	fn accrue() {
 		let mut sub_state = Substate::new();
-		let sub_state_2 = Substate::new();
+		sub_state.contracts_created.push(address_from_u64(1u64));
+		let mut sub_state_2 = Substate::new();
+		sub_state_2.contracts_created.push(address_from_u64(2u64));
 		sub_state.accrue(sub_state_2);
+		assert_eq!(sub_state.contracts_created.len(), 2);
 	}
 }
\ No newline at end of file
diff --git a/src/tests/executive.rs b/src/tests/executive.rs
index 1df1b7eec..f097a17ad 100644
--- a/src/tests/executive.rs
+++ b/src/tests/executive.rs
@@ -8,6 +8,7 @@ use evm::{Schedule, Ext, Factory, VMType, ContractCreateResult, MessageCallResul
 use ethereum;
 use externalities::*;
 use substate::*;
+use tests::helpers::*;
 
 struct TestEngine {
 	vm_factory: Factory,
@@ -174,7 +175,8 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 		};
 	
 		// test env
-		let mut state = State::new_temp();
+		let mut state_result = get_temp_state();
+		let mut state = state_result.reference_mut();
 
 		test.find("pre").map(|pre| for (addr, s) in pre.as_object().unwrap() {
 			let address = Address::from(addr.as_ref());
diff --git a/src/tests/helpers.rs b/src/tests/helpers.rs
index de73224fd..d2423f95c 100644
--- a/src/tests/helpers.rs
+++ b/src/tests/helpers.rs
@@ -5,7 +5,8 @@ use std::path::PathBuf;
 use spec::*;
 use std::fs::{remove_dir_all};
 use blockchain::{BlockChain};
-
+use state::*;
+use rocksdb::*;
 
 pub struct RandomTempPath {
 	path: PathBuf
@@ -23,6 +24,10 @@ impl RandomTempPath {
 	pub fn as_path(&self) -> &PathBuf {
 		&self.path
 	}
+
+	pub fn as_str(&self) -> &str {
+		self.path.to_str().unwrap()
+	}
 }
 
 impl Drop for RandomTempPath {
@@ -43,6 +48,10 @@ impl<T> GuardedTempResult<T> {
     pub fn reference(&self) -> &T {
         &self.result
     }
+
+    pub fn reference_mut(&mut self) -> &mut T {
+    	&mut self.result
+    }
 }
 
 pub fn get_test_spec() -> Spec {
@@ -189,6 +198,35 @@ pub fn generate_dummy_empty_blockchain() -> GuardedTempResult<BlockChain> {
 	}
 }
 
+pub fn get_temp_journal_db() -> GuardedTempResult<JournalDB> {
+	let temp = RandomTempPath::new();
+	let db = DB::open_default(temp.as_str()).unwrap();
+	let journal_db = JournalDB::new(db);
+	GuardedTempResult {
+		temp: temp,
+		result: journal_db
+	}
+}
+
+pub fn get_temp_state() -> GuardedTempResult<State> {
+	let temp = RandomTempPath::new();
+	let journal_db = get_temp_journal_db_in(temp.as_path());
+	GuardedTempResult {
+	    temp: temp,
+		result: State::new(journal_db, U256::from(0u8))
+	}
+}
+
+pub fn get_temp_journal_db_in(path: &Path) -> JournalDB {
+	let db = DB::open_default(path.to_str().unwrap()).unwrap();
+	JournalDB::new(db)
+}
+
+pub fn get_temp_state_in(path: &Path) -> State {
+	let journal_db = get_temp_journal_db_in(path);
+	State::new(journal_db, U256::from(0u8))
+}
+
 pub fn get_good_dummy_block() -> Bytes {
 	let mut block_header = Header::new();
 	let test_spec = get_test_spec();
diff --git a/src/tests/state.rs b/src/tests/state.rs
index 325a8b646..1dbe27c9c 100644
--- a/src/tests/state.rs
+++ b/src/tests/state.rs
@@ -1,8 +1,8 @@
 use super::test_common::*;
-use state::*;
 use pod_state::*;
 use state_diff::*;
 use ethereum;
+use tests::helpers::*;
 
 fn do_json_test(json_data: &[u8]) -> Vec<String> {
 	let json = Json::from_str(::std::str::from_utf8(json_data).unwrap()).expect("Json is invalid");
@@ -39,14 +39,15 @@ fn do_json_test(json_data: &[u8]) -> Vec<String> {
 				println!("!!! {}: Trie root mismatch (got: {}, expect: {}):", name, calc_post, post_state_root);
 				println!("!!! Post:\n{}", post);
 			} else {
-				let mut s = State::new_temp();
-				s.populate_from(pre);
-				s.commit();
-				let res = s.apply(&env, engine.deref(), &t);
+				let mut state_result = get_temp_state();
+				let mut state = state_result.reference_mut();
+				state.populate_from(pre);
+				state.commit();
+				let res = state.apply(&env, engine.deref(), &t);
 
-				if fail_unless(s.root() == &post_state_root) {
-					println!("!!! {}: State mismatch (got: {}, expect: {}):", name, s.root(), post_state_root);
-					let our_post = s.to_pod();
+				if fail_unless(state.root() == &post_state_root) {
+					println!("!!! {}: State mismatch (got: {}, expect: {}):", name, state.root(), post_state_root);
+					let our_post = state.to_pod();
 					println!("Got:\n{}", our_post);
 					println!("Expect:\n{}", post);
 					println!("Diff ---expect -> +++got:\n{}", StateDiff::diff_pod(&post, &our_post));
diff --git a/util/src/journaldb.rs b/util/src/journaldb.rs
index ba31efafb..858455072 100644
--- a/util/src/journaldb.rs
+++ b/util/src/journaldb.rs
@@ -19,7 +19,7 @@ pub struct JournalDB {
 	forward: OverlayDB,
 	backing: Arc<DB>,
 	inserts: Vec<H256>,
-	removes: Vec<H256>,
+	removes: Vec<H256>
 }
 
 impl JournalDB {
@@ -45,6 +45,7 @@ impl JournalDB {
 	}
 
 	/// Create a new instance with an anonymous temporary database.
+	#[cfg(test)]
 	pub fn new_temp() -> JournalDB {
 		let mut dir = env::temp_dir();
 		dir.push(H32::random().hex());
@@ -137,6 +138,7 @@ mod tests {
 	use common::*;
 	use super::*;
 	use hashdb::*;
+	use tests::helpers::*;
 
 	#[test]
 	fn long_history() {
@@ -221,4 +223,11 @@ mod tests {
 		assert!(!jdb.exists(&baz));
 		assert!(!jdb.exists(&bar));
 	}
+
+	#[test]
+	fn old_commits_applied() {
+		let mut dir = env::temp_dir();
+		dir.push(H32::random().hex());
+
+	}
 }