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"))]
+		}));
 	}
 }