diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 99c64773d..bc9d9257d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -549,7 +549,7 @@ test-darwin:
     - triggers
   before_script:
     - git submodule update --init --recursive
-    - export RUST_FILES_MODIFIED=$(git --no-pager diff --name-only $CI_BUILD_REF^ $CI_BUILD_REF | grep -v -e ^js -e ^\\. -e ^LICENSE -e ^README.md -e ^appveyor.yml -e ^test.sh -e ^windows/ -e ^scripts/ -e^mac/ -e ^nsis/ | wc -l)
+    - export RUST_FILES_MODIFIED=$(git --no-pager diff --name-only $CI_BUILD_REF^ $CI_BUILD_REF | grep -v -e "^js/" -e ^\\. -e ^LICENSE -e ^README.md -e ^appveyor.yml -e ^test.sh -e ^windows/ -e ^scripts/ -e^mac/ -e ^nsis/ | wc -l)
   script:
     - export RUST_BACKTRACE=1
     - if [ $RUST_FILES_MODIFIED -eq 0 ]; then echo "Skipping Rust tests since no Rust files modified."; else ./test.sh $CARGOFLAGS; fi
diff --git a/json/src/spec/account.rs b/json/src/spec/account.rs
index 046592a71..2c98fd3f1 100644
--- a/json/src/spec/account.rs
+++ b/json/src/spec/account.rs
@@ -39,7 +39,7 @@ pub struct Account {
 }
 
 impl Account {
-	/// Returns true if account does not have nonce and balance.
+	/// Returns true if account does not have nonce, balance, code and storage.
 	pub fn is_empty(&self) -> bool {
 		self.balance.is_none() && self.nonce.is_none() && self.code.is_none() && self.storage.is_none()
 	}
@@ -54,6 +54,59 @@ mod tests {
 	use uint::Uint;
 	use bytes::Bytes;
 
+	#[test]
+	fn account_balance_missing_not_empty() {
+		let s = r#"{
+			"nonce": "0",
+			"code": "1234",
+			"storage": { "0x7fffffffffffffff7fffffffffffffff": "0x1" }
+		}"#;
+		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(!deserialized.is_empty());
+	}
+
+	#[test]
+	fn account_nonce_missing_not_empty() {
+		let s = r#"{
+			"balance": "1",
+			"code": "1234",
+			"storage": { "0x7fffffffffffffff7fffffffffffffff": "0x1" }
+		}"#;
+		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(!deserialized.is_empty());
+	}
+
+	#[test]
+	fn account_code_missing_not_empty() {
+		let s = r#"{
+			"balance": "1",
+			"nonce": "0",
+			"storage": { "0x7fffffffffffffff7fffffffffffffff": "0x1" }
+		}"#;
+		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(!deserialized.is_empty());
+	}
+
+	#[test]
+	fn account_storage_missing_not_empty() {
+		let s = r#"{
+			"balance": "1",
+			"nonce": "0",
+			"code": "1234"
+		}"#;
+		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(!deserialized.is_empty());
+	}
+
+	#[test]
+	fn account_empty() {
+		let s = r#"{
+			"builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } }
+		}"#;
+		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(deserialized.is_empty());
+	}
+
 	#[test]
 	fn account_deserialization() {
 		let s = r#"{
@@ -63,6 +116,7 @@ mod tests {
 			"code": "1234"
 		}"#;
 		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(!deserialized.is_empty());
 		assert_eq!(deserialized.balance.unwrap(), Uint(U256::from(1)));
 		assert_eq!(deserialized.nonce.unwrap(), Uint(U256::from(0)));
 		assert_eq!(deserialized.code.unwrap(), Bytes::new(vec![0x12, 0x34]));
@@ -78,6 +132,7 @@ mod tests {
 			"storage": { "0x7fffffffffffffff7fffffffffffffff": "0x1" }
 		}"#;
 		let deserialized: Account = serde_json::from_str(s).unwrap();
+		assert!(!deserialized.is_empty());
 		assert_eq!(deserialized.balance.unwrap(), Uint(U256::from(1)));
 		assert_eq!(deserialized.nonce.unwrap(), Uint(U256::from(0)));
 		assert_eq!(deserialized.code.unwrap(), Bytes::new(vec![0x12, 0x34]));
diff --git a/json/src/spec/authority_round.rs b/json/src/spec/authority_round.rs
index 99d138d00..ae518eebc 100644
--- a/json/src/spec/authority_round.rs
+++ b/json/src/spec/authority_round.rs
@@ -60,7 +60,12 @@ pub struct AuthorityRound {
 
 #[cfg(test)]
 mod tests {
+	use uint::Uint;
+	use util::U256;
+	use util::H160;
 	use serde_json;
+	use hash::Address;
+	use spec::validator_set::ValidatorSet;
 	use spec::authority_round::AuthorityRound;
 
 	#[test]
@@ -79,6 +84,13 @@ mod tests {
 			}
 		}"#;
 
-		let _deserialized: AuthorityRound = serde_json::from_str(s).unwrap();
+		let deserialized: AuthorityRound = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized.params.gas_limit_bound_divisor, Uint(U256::from(0x0400)));
+		assert_eq!(deserialized.params.step_duration, Uint(U256::from(0x02)));
+		assert_eq!(deserialized.params.validators, ValidatorSet::List(vec![Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))]));
+		assert_eq!(deserialized.params.block_reward, Some(Uint(U256::from(0x50))));
+		assert!(deserialized.params.registrar.is_none());
+		assert_eq!(deserialized.params.start_step, Some(Uint(U256::from(24))));
+		assert_eq!(deserialized.params.eip155_transition, Some(Uint(U256::from(0x42))));
 	}
 }
diff --git a/json/src/spec/basic_authority.rs b/json/src/spec/basic_authority.rs
index 06f50268e..01fe8f088 100644
--- a/json/src/spec/basic_authority.rs
+++ b/json/src/spec/basic_authority.rs
@@ -42,7 +42,12 @@ pub struct BasicAuthority {
 #[cfg(test)]
 mod tests {
 	use serde_json;
+	use uint::Uint;
+	use util::U256;
+	use hash::Address;
+	use util::hash::H160;
 	use spec::basic_authority::BasicAuthority;
+	use spec::validator_set::ValidatorSet;
 
 	#[test]
 	fn basic_authority_deserialization() {
@@ -56,6 +61,11 @@ mod tests {
 			}
 		}"#;
 
-		let _deserialized: BasicAuthority = serde_json::from_str(s).unwrap();
+		let deserialized: BasicAuthority = serde_json::from_str(s).unwrap();
+
+		assert_eq!(deserialized.params.gas_limit_bound_divisor, Uint(U256::from(0x0400)));
+		assert_eq!(deserialized.params.duration_limit, Uint(U256::from(0x0d)));
+		let vs = ValidatorSet::List(vec![Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))]);
+		assert_eq!(deserialized.params.validators, vs);
 	}
 }
diff --git a/json/src/spec/engine.rs b/json/src/spec/engine.rs
index ef54c4ab1..5706b0680 100644
--- a/json/src/spec/engine.rs
+++ b/json/src/spec/engine.rs
@@ -58,7 +58,11 @@ mod tests {
 			"instantSeal": { "params": {} }
 		}"#;
 
-		let _deserialized: Engine = serde_json::from_str(s).unwrap();
+		let deserialized: Engine = serde_json::from_str(s).unwrap();
+		match deserialized {
+			Engine::InstantSeal(_) => {},	// instant seal is unit tested in its own file.
+			_ => assert!(false),
+		};
 
 		let s = r#"{
 			"Ethash": {
@@ -77,7 +81,66 @@ mod tests {
 			}
 		}"#;
 
-		let _deserialized: Engine = serde_json::from_str(s).unwrap();
+		let deserialized: Engine = serde_json::from_str(s).unwrap();
+		match deserialized {
+			Engine::Ethash(_) => {},	// ethash is unit tested in its own file.
+			_ => assert!(false),
+		};
+
+		let s = r#"{
+			"basicAuthority": {
+				"params": {
+					"gasLimitBoundDivisor": "0x0400",
+					"durationLimit": "0x0d",
+					"validators" : {
+						"list": ["0xc6d9d2cd449a754c494264e1809c50e34d64562b"]
+					}
+				}
+			}
+		}"#;
+		let deserialized: Engine = serde_json::from_str(s).unwrap();
+		match deserialized {
+			Engine::BasicAuthority(_) => {}, // basicAuthority is unit tested in its own file.
+			_ => assert!(false),
+		};
+
+		let s = r#"{
+			"authorityRound": {
+				"params": {
+					"gasLimitBoundDivisor": "0x0400",
+					"stepDuration": "0x02",
+					"validators": {
+						"list" : ["0xc6d9d2cd449a754c494264e1809c50e34d64562b"]
+					},
+					"blockReward": "0x50",
+					"startStep" : 24,
+					"eip155Transition": "0x42",
+					"validateStepTransition": 150
+				}
+			}
+		}"#;
+		let deserialized: Engine = serde_json::from_str(s).unwrap();
+		match deserialized {
+			Engine::AuthorityRound(_) => {}, // AuthorityRound is unit tested in its own file.
+			_ => assert!(false),
+		};
+
+		let s = r#"{
+			"tendermint": {
+				"params": {
+					"gasLimitBoundDivisor": "0x0400",
+					"validators": {
+						"list": ["0xc6d9d2cd449a754c494264e1809c50e34d64562b"]
+					},
+					"blockReward": "0x50"
+				}
+			}
+		}"#;
+		let deserialized: Engine = serde_json::from_str(s).unwrap();
+		match deserialized {
+			Engine::Tendermint(_) => {}, // Tendermint is unit tested in its own file.
+			_ => assert!(false),
+		};
 	}
 }
 
diff --git a/json/src/spec/ethash.rs b/json/src/spec/ethash.rs
index 16d05a18f..926dcacee 100644
--- a/json/src/spec/ethash.rs
+++ b/json/src/spec/ethash.rs
@@ -131,7 +131,11 @@ pub struct Ethash {
 #[cfg(test)]
 mod tests {
 	use serde_json;
-	use spec::ethash::Ethash;
+	use uint::Uint;
+	use util::U256;
+	use hash::Address;
+	use util::hash::H160;
+	use spec::ethash::{Ethash, EthashParams};
 
 	#[test]
 	fn ethash_deserialization() {
@@ -170,17 +174,71 @@ mod tests {
 				],
 				"difficultyHardforkTransition": "0x59d9",
 				"difficultyHardforkBoundDivisor": "0x0200",
-				"bombDefuseTransition": "0x42",
+				"bombDefuseTransition": "0x41",
 				"eip100bTransition": "0x42",
-				"eip150Transition": "0x42",
-				"eip155Transition": "0x42",
-				"eip160Transition": "0x42",
-				"eip161abcTransition": "0x42",
-				"eip161dTransition": "0x42"
+				"eip150Transition": "0x43",
+				"eip155Transition": "0x44",
+				"eip160Transition": "0x45",
+				"eip161abcTransition": "0x46",
+				"eip161dTransition": "0x47"
 			}
 		}"#;
 
-		let _deserialized: Ethash = serde_json::from_str(s).unwrap();
+		let deserialized: Ethash = serde_json::from_str(s).unwrap();
+
+		assert_eq!(deserialized, Ethash{
+			params: EthashParams{
+				gas_limit_bound_divisor: Uint(U256::from(0x0400)),
+				minimum_difficulty: Uint(U256::from(0x020000)),
+				difficulty_bound_divisor: Uint(U256::from(0x0800)),
+				difficulty_increment_divisor: None,
+				metropolis_difficulty_increment_divisor: None,
+				duration_limit: Uint(U256::from(0x0d)),
+				block_reward: Uint(U256::from(0x4563918244F40000u64)),
+				registrar: Some(Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))),
+				homestead_transition: Some(Uint(U256::from(0x42))),
+				dao_hardfork_transition: Some(Uint(U256::from(0x08))),
+				dao_hardfork_beneficiary: Some(Address(H160::from("0xabcabcabcabcabcabcabcabcabcabcabcabcabca"))),
+				dao_hardfork_accounts: Some(vec![
+					Address(H160::from("0x304a554a310c7e546dfe434669c62820b7d83490")),
+					Address(H160::from("0x914d1b8b43e92723e64fd0a06f5bdb8dd9b10c79")),
+					Address(H160::from("0xfe24cdd8648121a43a7c86d289be4dd2951ed49f")),
+					Address(H160::from("0x17802f43a0137c506ba92291391a8a8f207f487d")),
+					Address(H160::from("0xb136707642a4ea12fb4bae820f03d2562ebff487")),
+					Address(H160::from("0xdbe9b615a3ae8709af8b93336ce9b477e4ac0940")),
+					Address(H160::from("0xf14c14075d6c4ed84b86798af0956deef67365b5")),
+					Address(H160::from("0xca544e5c4687d109611d0f8f928b53a25af72448")),
+					Address(H160::from("0xaeeb8ff27288bdabc0fa5ebb731b6f409507516c")),
+					Address(H160::from("0xcbb9d3703e651b0d496cdefb8b92c25aeb2171f7")),
+					Address(H160::from("0xaccc230e8a6e5be9160b8cdf2864dd2a001c28b6")),
+					Address(H160::from("0x2b3455ec7fedf16e646268bf88846bd7a2319bb2")),
+					Address(H160::from("0x4613f3bca5c44ea06337a9e439fbc6d42e501d0a")),
+					Address(H160::from("0xd343b217de44030afaa275f54d31a9317c7f441e")),
+					Address(H160::from("0x84ef4b2357079cd7a7c69fd7a37cd0609a679106")),
+					Address(H160::from("0xda2fef9e4a3230988ff17df2165440f37e8b1708")),
+					Address(H160::from("0xf4c64518ea10f995918a454158c6b61407ea345c")),
+					Address(H160::from("0x7602b46df5390e432ef1c307d4f2c9ff6d65cc97")),
+					Address(H160::from("0xbb9bc244d798123fde783fcc1c72d3bb8c189413")),
+					Address(H160::from("0x807640a13483f8ac783c557fcdf27be11ea4ac7a")),
+				]),
+				difficulty_hardfork_transition: Some(Uint(U256::from(0x59d9))),
+				difficulty_hardfork_bound_divisor: Some(Uint(U256::from(0x0200))),
+				bomb_defuse_transition: Some(Uint(U256::from(0x41))),
+				eip100b_transition: Some(Uint(U256::from(0x42))),
+				eip150_transition: Some(Uint(U256::from(0x43))),
+				eip155_transition: Some(Uint(U256::from(0x44))),
+				eip160_transition: Some(Uint(U256::from(0x45))),
+				eip161abc_transition: Some(Uint(U256::from(0x46))),
+				eip161d_transition: Some(Uint(U256::from(0x47))),
+				ecip1010_pause_transition: None,
+				ecip1010_continue_transition: None,
+				max_code_size: None,
+				max_gas_limit_transition: None,
+				max_gas_limit: None,
+				min_gas_price_transition: None,
+				min_gas_price: None,
+			}
+		});
 	}
 
 	#[test]
@@ -195,6 +253,38 @@ mod tests {
 			}
 		}"#;
 
-		let _deserialized: Ethash = serde_json::from_str(s).unwrap();
+		let deserialized: Ethash = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized, Ethash{
+			params: EthashParams{
+				gas_limit_bound_divisor: Uint(U256::from(0x0400)),
+				minimum_difficulty: Uint(U256::from(0x020000)),
+				difficulty_bound_divisor: Uint(U256::from(0x0800)),
+				difficulty_increment_divisor: None,
+				metropolis_difficulty_increment_divisor: None,
+				duration_limit: Uint(U256::from(0x0d)),
+				block_reward: Uint(U256::from(0x4563918244F40000u64)),
+				registrar: None,
+				homestead_transition: None,
+				dao_hardfork_transition: None,
+				dao_hardfork_beneficiary: None,
+				dao_hardfork_accounts: None,
+				difficulty_hardfork_transition: None,
+				difficulty_hardfork_bound_divisor: None,
+				bomb_defuse_transition: None,
+				eip100b_transition: None,
+				eip150_transition: None,
+				eip155_transition: None,
+				eip160_transition: None,
+				eip161abc_transition: None,
+				eip161d_transition: None,
+				ecip1010_pause_transition: None,
+				ecip1010_continue_transition: None,
+				max_code_size: None,
+				max_gas_limit_transition: None,
+				max_gas_limit: None,
+				min_gas_price_transition: None,
+				min_gas_price: None,
+			}
+		});
 	}
 }
diff --git a/json/src/spec/genesis.rs b/json/src/spec/genesis.rs
index 6f69f8c14..120df4fc1 100644
--- a/json/src/spec/genesis.rs
+++ b/json/src/spec/genesis.rs
@@ -58,7 +58,15 @@ pub struct Genesis {
 #[cfg(test)]
 mod tests {
 	use serde_json;
+	use bytes::Bytes;
+	use uint::Uint;
+	use util::U256;
+	use hash::{H64, H256, Address};
+	use util::hash::H160;
+	use util::{H64 as Eth64, H256 as Eth256};
 	use spec::genesis::Genesis;
+	use spec::{Ethereum, Seal};
+	use std::str::FromStr;
 
 	#[test]
 	fn genesis_deserialization() {
@@ -71,14 +79,29 @@ mod tests {
 					"nonce": "0x00006d6f7264656e"
 				}
 			},
-			"author": "0x0000000000000000000000000000000000000000",
-			"timestamp": "0x00",
-			"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+			"author": "0x1000000000000000000000000000000000000001",
+			"timestamp": "0x07",
+			"parentHash": "0x9000000000000000000000000000000000000000000000000000000000000000",
 			"extraData": "0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa",
 			"gasLimit": "0x1388",
 			"stateRoot": "0xd7f8974fb5ac78d9ac099b9ad5018bedc2ce0a72dad1827a1709da30580f0544"
 		}"#;
-		let _deserialized: Genesis = serde_json::from_str(s).unwrap();
-		// TODO: validate all fields
+		let deserialized: Genesis = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized, Genesis {
+			seal: Seal::Ethereum(Ethereum {
+				nonce: H64(Eth64::from("0x00006d6f7264656e")),
+				mix_hash: H256(Eth256::from("0x0000000000000000000000000000000000000000000000000000000000000000"))
+			}),
+			difficulty: Uint(U256::from(0x400000000u64)),
+			author: Some(Address(H160::from("0x1000000000000000000000000000000000000001"))),
+			timestamp: Some(Uint(U256::from(0x07))),
+			parent_hash: Some(H256(Eth256::from("0x9000000000000000000000000000000000000000000000000000000000000000"))),
+			gas_limit: Uint(U256::from(0x1388)),
+			transactions_root: None,
+			receipts_root: None,
+			state_root: Some(H256(Eth256::from("0xd7f8974fb5ac78d9ac099b9ad5018bedc2ce0a72dad1827a1709da30580f0544"))),
+			gas_used: None,
+			extra_data: Some(Bytes::from_str("0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa").unwrap()),
+		});
 	}
 }
diff --git a/json/src/spec/instant_seal.rs b/json/src/spec/instant_seal.rs
index 168b51c68..ebf167d28 100644
--- a/json/src/spec/instant_seal.rs
+++ b/json/src/spec/instant_seal.rs
@@ -35,6 +35,8 @@ pub struct InstantSeal {
 #[cfg(test)]
 mod tests {
 	use serde_json;
+	use hash::Address;
+	use util::hash::H160;
 	use spec::instant_seal::InstantSeal;
 
 	#[test]
@@ -45,6 +47,7 @@ mod tests {
 			}
 		}"#;
 
-		let _deserialized: InstantSeal = serde_json::from_str(s).unwrap();
+		let deserialized: InstantSeal = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized.params.registrar, Some(Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))));
 	}
 }
diff --git a/json/src/spec/params.rs b/json/src/spec/params.rs
index 824466ffc..5d5367791 100644
--- a/json/src/spec/params.rs
+++ b/json/src/spec/params.rs
@@ -67,21 +67,27 @@ pub struct Params {
 #[cfg(test)]
 mod tests {
 	use serde_json;
+	use uint::Uint;
+	use util::U256;
 	use spec::params::Params;
 
 	#[test]
 	fn params_deserialization() {
 		let s = r#"{
-			"homesteadTransition": "0x118c30",
 			"maximumExtraDataSize": "0x20",
 			"networkID" : "0x1",
 			"chainID" : "0x15",
 			"subprotocolName" : "exp",
 			"minGasLimit": "0x1388",
-			"accountStartNonce": "0x00"
+			"accountStartNonce": "0x01"
 		}"#;
 
-		let _deserialized: Params = serde_json::from_str(s).unwrap();
-		// TODO: validate all fields
+		let deserialized: Params = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized.maximum_extra_data_size, Uint(U256::from(0x20)));
+		assert_eq!(deserialized.network_id, Uint(U256::from(0x1)));
+		assert_eq!(deserialized.chain_id, Some(Uint(U256::from(0x15))));
+		assert_eq!(deserialized.subprotocol_name, Some("exp".to_owned()));
+		assert_eq!(deserialized.min_gas_limit, Uint(U256::from(0x1388)));
+		assert_eq!(deserialized.account_start_nonce, Some(Uint(U256::from(0x01))));
 	}
 }
diff --git a/json/src/spec/seal.rs b/json/src/spec/seal.rs
index 247bceb22..7345a623d 100644
--- a/json/src/spec/seal.rs
+++ b/json/src/spec/seal.rs
@@ -70,32 +70,62 @@ pub enum Seal {
 #[cfg(test)]
 mod tests {
 	use serde_json;
-	use spec::Seal;
+	use hash::*;
+	use bytes::Bytes;
+	use uint::Uint;
+	use util::U256;
+	use util::{H64 as Eth64, H256 as Eth256, H520 as Eth520};
+	use spec::{Ethereum, AuthorityRoundSeal, TendermintSeal, Seal};
 
 	#[test]
 	fn seal_deserialization() {
 		let s = r#"[{
 			"ethereum": {
 				"nonce": "0x0000000000000042",
-				"mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
+				"mixHash": "0x1000000000000000000000000000000000000000000000000000000000000001"
 			}
 		},{
 			"generic": "0xe011bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa"
 		},{
 			"authorityRound": {
 				"step": "0x0",
-				"signature": "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
+				"signature": "0x2000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002"
 			}
 		},{
 			"tendermint": {
-				"round": "0x0",
-				"proposal": "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+				"round": "0x3",
+				"proposal": "0x3000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000003",
 				"precommits": [
-					"0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
+					"0x4000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004"
 				]
 			}
 		}]"#;
-		let _deserialized: Vec<Seal> = serde_json::from_str(s).unwrap();
-		// TODO: validate all fields
+
+		let deserialized: Vec<Seal> = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized.len(), 4);
+
+		// [0]
+		assert_eq!(deserialized[0], Seal::Ethereum(Ethereum {
+			nonce: H64(Eth64::from("0x0000000000000042")),
+			mix_hash: H256(Eth256::from("0x1000000000000000000000000000000000000000000000000000000000000001"))
+		}));
+
+		// [1]
+		assert_eq!(deserialized[1], Seal::Generic(Bytes::new(vec![
+			0xe0, 0x11, 0xbb, 0xe8, 0xdb, 0x4e, 0x34, 0x7b, 0x4e, 0x8c, 0x93, 0x7c, 0x1c, 0x83, 0x70, 0xe4,
+			0xb5, 0xed, 0x33, 0xad, 0xb3, 0xdb, 0x69, 0xcb, 0xdb, 0x7a, 0x38, 0xe1, 0xe5, 0x0b, 0x1b, 0x82, 0xfa])));
+
+		// [2]
+		assert_eq!(deserialized[2], Seal::AuthorityRound(AuthorityRoundSeal {
+			step: Uint(U256::from(0x0)),
+			signature: H520(Eth520::from("0x2000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002"))
+		}));
+
+		// [3]
+		assert_eq!(deserialized[3], Seal::Tendermint(TendermintSeal {
+			round: Uint(U256::from(0x3)),
+			proposal: H520(Eth520::from("0x3000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000003")),
+			precommits: vec![H520(Eth520::from("0x4000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000004"))]
+		}));
 	}
 }
diff --git a/json/src/spec/tendermint.rs b/json/src/spec/tendermint.rs
index 16c2d7255..5a15a0841 100644
--- a/json/src/spec/tendermint.rs
+++ b/json/src/spec/tendermint.rs
@@ -57,7 +57,12 @@ pub struct Tendermint {
 #[cfg(test)]
 mod tests {
 	use serde_json;
+	use uint::Uint;
+	use util::U256;
+	use hash::Address;
+	use util::hash::H160;
 	use spec::tendermint::Tendermint;
+	use spec::validator_set::ValidatorSet;
 
 	#[test]
 	fn tendermint_deserialization() {
@@ -71,6 +76,10 @@ mod tests {
 			}
 		}"#;
 
-		let _deserialized: Tendermint = serde_json::from_str(s).unwrap();
+		let deserialized: Tendermint = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized.params.gas_limit_bound_divisor, Uint(U256::from(0x0400)));
+		let vs = ValidatorSet::List(vec![Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))]);
+		assert_eq!(deserialized.params.validators, vs);
+		assert_eq!(deserialized.params.block_reward, Some(Uint(U256::from(0x50))));
 	}
 }
diff --git a/json/src/spec/validator_set.rs b/json/src/spec/validator_set.rs
index f433caa03..abcb35848 100644
--- a/json/src/spec/validator_set.rs
+++ b/json/src/spec/validator_set.rs
@@ -40,6 +40,10 @@ pub enum ValidatorSet {
 #[cfg(test)]
 mod tests {
 	use serde_json;
+	use uint::Uint;
+	use util::U256;
+	use hash::Address;
+	use util::hash::H160;
 	use spec::validator_set::ValidatorSet;
 
 	#[test]
@@ -58,6 +62,20 @@ mod tests {
 			}
 		}]"#;
 
-		let _deserialized: Vec<ValidatorSet> = serde_json::from_str(s).unwrap();
+		let deserialized: Vec<ValidatorSet> = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized.len(), 4);
+
+		assert_eq!(deserialized[0], ValidatorSet::List(vec![Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))]));
+		assert_eq!(deserialized[1], ValidatorSet::SafeContract(Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))));
+		assert_eq!(deserialized[2], ValidatorSet::Contract(Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))));
+		match deserialized[3] {
+			ValidatorSet::Multi(ref map) => {
+				assert_eq!(map.len(), 3);
+				assert!(map.contains_key(&Uint(U256::from(0))));
+				assert!(map.contains_key(&Uint(U256::from(10))));
+				assert!(map.contains_key(&Uint(U256::from(20))));
+			},
+			_ => assert!(false),
+		}
 	}
 }