diff --git a/chain/src/indexed_block.rs b/chain/src/indexed_block.rs
index 22ac74b0..7297bcf5 100644
--- a/chain/src/indexed_block.rs
+++ b/chain/src/indexed_block.rs
@@ -84,3 +84,18 @@ impl From<&'static str> for IndexedBlock {
 		deserialize(&s.from_hex().unwrap() as &[u8]).unwrap()
 	}
 }
+
+#[cfg(test)]
+mod tests {
+	use super::IndexedBlock;
+
+	#[test]
+	fn size_with_witness_not_equal_to_size() {
+		let block_without_witness: IndexedBlock = "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000".into();
+		assert_eq!(block_without_witness.size(), block_without_witness.size_with_witness());
+
+		// bip143 block
+		let block_with_witness: IndexedBlock = "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000010100000000000000000000000000000000000000000000000000000000000000000000000000000000000001010000000000".into();
+		assert!(block_with_witness.size() != block_with_witness.size_with_witness());
+	}
+}
diff --git a/chain/src/transaction.rs b/chain/src/transaction.rs
index 2fcf87c7..b84dd0ed 100644
--- a/chain/src/transaction.rs
+++ b/chain/src/transaction.rs
@@ -262,7 +262,7 @@ impl Deserializable for Transaction {
 #[cfg(test)]
 mod tests {
 	use hash::H256;
-	use ser::Serializable;
+	use ser::{Serializable, serialize_with_flags, SERIALIZE_TRANSACTION_WITNESS};
 	use super::{Transaction, TransactionInput, OutPoint, TransactionOutput};
 
 	// real transaction from block 80000
@@ -335,4 +335,13 @@ mod tests {
 		};
 		assert_eq!(actual, expected);
 	}
+
+	#[test]
+	fn test_serialization_with_flags() {
+		let transaction_without_witness: Transaction = "000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000".into();
+		assert_eq!(serialize_with_flags(&transaction_without_witness, 0), serialize_with_flags(&transaction_without_witness, SERIALIZE_TRANSACTION_WITNESS));
+
+		let transaction_with_witness: Transaction = "0000000000010100000000000000000000000000000000000000000000000000000000000000000000000000000000000001010000000000".into();
+		assert!(serialize_with_flags(&transaction_with_witness, 0) != serialize_with_flags(&transaction_with_witness, SERIALIZE_TRANSACTION_WITNESS));
+	}
 }