diff --git a/db/src/storage.rs b/db/src/storage.rs
index 15cdb71a..3f117e11 100644
--- a/db/src/storage.rs
+++ b/db/src/storage.rs
@@ -385,34 +385,9 @@ mod tests {
 
 	use super::{Storage, Store};
 	use devtools::RandomTempPath;
-	use chain::{
-		Block, BlockHeader, Transaction, RepresentH256, TransactionOutput,
-		TransactionInput, OutPoint,
-	};
+	use chain::{Block, RepresentH256};
 	use super::super::BlockRef;
 	use test_data;
-	use primitives::hash::H256;
-	use primitives::bytes::Bytes;
-
-	fn dummy_coinbase_tx() -> Transaction {
-		Transaction {
-			version: 0,
-			inputs: vec![
-				TransactionInput {
-					previous_output: OutPoint { hash: H256::from(0), index: 0xffffffff },
-					script_sig: Bytes::new_with_len(0),
-					sequence: 0
-				}
-			],
-			outputs: vec![
-				TransactionOutput {
-					value: 0,
-					script_pubkey: Bytes::new_with_len(0),
-				}
-			],
-			lock_time: 0,
-		}
-	}
 
 	#[test]
 	fn open_store() {
@@ -505,36 +480,15 @@ mod tests {
 		let genesis_meta = store.transaction_meta(&genesis_coinbase).unwrap();
 		assert!(!genesis_meta.is_spent(0));
 
-		let forged_block = Block::new(
-			BlockHeader {
-				version: 0,
-				previous_header_hash: genesis.hash(),
-				merkle_root_hash: H256::from(0),
-				nbits: 0,
-				time: 0,
-				nonce: 0,
-			},
-			vec![
-				dummy_coinbase_tx(),
-				Transaction {
-					version: 0,
-					inputs: vec![
-						TransactionInput {
-							previous_output: OutPoint { hash: genesis_coinbase.clone(), index: 0 },
-							script_sig: Bytes::new_with_len(0),
-							sequence: 0
-						}
-					],
-					outputs: vec![
-						TransactionOutput {
-							value: 0,
-							script_pubkey: Bytes::new_with_len(0),
-						}
-					],
-					lock_time: 0,
-				},
-			]
-		);
+		let forged_block = test_data::block_builder()
+			.header().parent(genesis.hash()).build()
+			.transaction().coinbase().build()
+			.transaction()
+				.input().hash(genesis_coinbase.clone()).build()
+				.output().build()
+				.build()
+			.build();
+
 		store.insert_block(&forged_block).unwrap();
 
 		let genesis_meta = store.transaction_meta(&genesis_coinbase).unwrap();
diff --git a/test-data/src/block.rs b/test-data/src/block.rs
new file mode 100644
index 00000000..f3775dd9
--- /dev/null
+++ b/test-data/src/block.rs
@@ -0,0 +1,350 @@
+//! Block builder
+
+use chain;
+use primitives::hash::H256;
+use primitives::bytes::Bytes;
+use invoke::{Invoke, Identity};
+
+pub struct BlockBuilder<F=Identity> {
+	callback: F,
+	header: Option<chain::BlockHeader>,
+	transactions: Vec<chain::Transaction>,
+}
+
+impl BlockBuilder {
+	pub fn new() -> Self {
+		BlockBuilder::with_callback(Identity)
+	}
+}
+
+impl<F> BlockBuilder<F> where F: Invoke<chain::Block> {
+	pub fn with_callback(callback: F) -> Self {
+		BlockBuilder {
+			callback: callback,
+			header: None,
+			transactions: Vec::new(),
+		}
+	}
+
+	pub fn with_header(mut self, header: chain::BlockHeader) -> Self {
+		self.header = Some(header);
+		self
+	}
+
+	pub fn with_transaction(mut self, transaction: chain::Transaction) -> Self {
+		self.transactions.push(transaction);
+		self
+	}
+
+	pub fn with_transactions<I>(mut self, txs: I) -> Self
+		where I: IntoIterator<Item=chain::Transaction>
+	{
+		self.transactions.extend(txs);
+		self
+	}
+
+	pub fn with_raw(mut self, raw: &'static str) -> Self {
+		let raw_block: chain::Block = raw.into();
+		self.transactions = raw_block.transactions.to_vec();
+		self.header = Some(raw_block.header().clone());
+		self
+	}
+
+	pub fn header(self) -> BlockHeaderBuilder<Self> {
+		BlockHeaderBuilder::with_callback(self)
+	}
+
+	pub fn transaction(self) -> TransactionBuilder<Self> {
+		TransactionBuilder::with_callback(self)
+	}
+
+	pub fn build(self) -> F::Result {
+		self.callback.invoke(
+			chain::Block::new(
+				self.header.unwrap(),
+				self.transactions,
+			)
+		)
+	}
+}
+
+impl<F> Invoke<chain::BlockHeader> for BlockBuilder<F>
+	where F: Invoke<chain::Block>
+{
+	type Result = Self;
+
+	fn invoke(self, header: chain::BlockHeader) -> Self {
+		self.with_header(header)
+	}
+}
+
+impl<F> Invoke<chain::Transaction> for BlockBuilder<F>
+	where F: Invoke<chain::Block>
+{
+	type Result = Self;
+
+	fn invoke(self, tx: chain::Transaction) -> Self {
+		self.with_transaction(tx)
+	}
+}
+
+pub struct BlockHeaderBuilder<F=Identity> {
+	callback: F,
+	time: u32,
+	parent: H256,
+	nonce: u32,
+	nbits: u32,
+	version: u32,
+	merkle_root: H256,
+}
+
+impl<F> BlockHeaderBuilder<F> where F: Invoke<chain::BlockHeader> {
+	pub fn with_callback(callback: F) -> Self {
+		BlockHeaderBuilder {
+			callback: callback,
+			time: 0,
+			nonce: 0,
+			merkle_root: H256::from(0),
+			parent: H256::from(0),
+			nbits: 0,
+			version: 1,
+		}
+	}
+
+	pub fn parent(mut self, parent: H256) -> Self {
+		self.parent = parent;
+		self
+	}
+
+	pub fn time(mut self, time: u32) -> Self {
+		self.time = time;
+		self
+	}
+
+	pub fn merkle_root(mut self, merkle_root: H256) -> Self {
+		self.merkle_root = merkle_root;
+		self
+	}
+
+	pub fn nbits(mut self, nbits: u32) -> Self {
+		self.nbits = nbits;
+		self
+	}
+
+	pub fn nonce(mut self, nonce: u32) -> Self {
+		self.nonce = nonce;
+		self
+	}
+
+	pub fn build(self) -> F::Result {
+		self.callback.invoke(
+			chain::BlockHeader {
+				time: self.time,
+				previous_header_hash: self.parent,
+				nbits: self.nbits,
+				nonce: self.nonce,
+				merkle_root_hash: self.merkle_root,
+				version: self.version,
+			}
+		)
+	}
+}
+
+pub struct TransactionBuilder<F=Identity> {
+	callback: F,
+	version: i32,
+	lock_time: u32,
+	inputs: Vec<chain::TransactionInput>,
+	outputs: Vec<chain::TransactionOutput>,
+}
+
+impl<F> TransactionBuilder<F> where F: Invoke<chain::Transaction> {
+	fn with_callback(callback: F) -> Self {
+		TransactionBuilder {
+			callback: callback,
+			version: 1,
+			lock_time: 0,
+			inputs: Vec::new(),
+			outputs: Vec::new(),
+		}
+	}
+
+	fn with_input(mut self, input: chain::TransactionInput) -> Self {
+		self.inputs.push(input);
+		self
+	}
+
+	fn with_output(mut self, input: chain::TransactionOutput) -> Self {
+		self.outputs.push(input);
+		self
+	}
+
+	pub fn lock_time(mut self, time: u32) -> Self {
+		self.lock_time = time;
+		self
+	}
+
+	pub fn input(self) -> TransactionInputBuilder<Self> {
+		TransactionInputBuilder::with_callback(self)
+	}
+
+	pub fn coinbase(self) -> Self {
+		self.input().coinbase().build()
+	}
+
+	pub fn output(self) -> TransactionOutputBuilder<Self> {
+		TransactionOutputBuilder::with_callback(self)
+	}
+
+	pub fn build(self) -> F::Result {
+		self.callback.invoke(
+			chain::Transaction {
+				lock_time: self.lock_time,
+				version: self.version,
+				inputs: self.inputs,
+				outputs: self.outputs,
+			}
+		)
+	}
+}
+
+
+impl<F> Invoke<chain::TransactionInput> for TransactionBuilder<F>
+	where F: Invoke<chain::Transaction>
+{
+	type Result = Self;
+
+	fn invoke(self, tx: chain::TransactionInput) -> Self {
+		self.with_input(tx)
+	}
+}
+
+impl<F> Invoke<chain::TransactionOutput> for TransactionBuilder<F>
+	where F: Invoke<chain::Transaction>
+{
+	type Result = Self;
+
+	fn invoke(self, tx: chain::TransactionOutput) -> Self {
+		self.with_output(tx)
+	}
+}
+
+pub struct TransactionInputBuilder<F=Identity> {
+	callback: F,
+	output: Option<chain::OutPoint>,
+	signature: Bytes,
+	sequence: u32,
+}
+
+impl<F> TransactionInputBuilder<F> where F: Invoke<chain::TransactionInput> {
+	fn with_callback(callback: F) -> Self {
+		TransactionInputBuilder {
+			callback: callback,
+			output: None,
+			signature: Bytes::new_with_len(0),
+			sequence: 0,
+		}
+	}
+
+	pub fn hash(mut self, hash: H256) -> Self {
+		let mut output = self.output.unwrap_or(chain::OutPoint { hash: hash.clone(), index: 0 });
+		output.hash = hash;
+		self.output = Some(output);
+		self
+	}
+
+	pub fn index(mut self, index: u32) -> Self {
+		let mut output = self.output.unwrap_or(chain::OutPoint { hash: H256::from(0), index: index });
+		output.index = index;
+		self.output = Some(output);
+		self
+	}
+
+	pub fn coinbase(mut self) -> Self {
+		self.output = Some(chain::OutPoint { hash: H256::from(0), index: 0xffffffff });
+		self
+	}
+
+	pub fn build(self) -> F::Result {
+		self.callback.invoke(
+			chain::TransactionInput {
+				previous_output: self.output.unwrap_or_else(|| panic!("Building input without previous output")),
+				script_sig: self.signature,
+				sequence: self.sequence,
+			}
+		)
+	}
+}
+
+
+pub struct TransactionOutputBuilder<F=Identity> {
+	callback: F,
+	value: u64,
+	signature: Bytes,
+}
+
+impl<F> TransactionOutputBuilder<F> where F: Invoke<chain::TransactionOutput> {
+	fn with_callback(callback: F) -> Self {
+		TransactionOutputBuilder {
+			callback: callback,
+			signature: Bytes::new_with_len(0),
+			value: 0,
+		}
+	}
+
+	pub fn value(mut self, value: u64) -> Self {
+		self.value = value;
+		self
+	}
+
+	pub fn build(self) -> F::Result {
+		self.callback.invoke(
+			chain::TransactionOutput {
+				script_pubkey: self.signature,
+				value: self.value,
+			}
+		)
+	}
+}
+
+pub fn block_builder() -> BlockBuilder { BlockBuilder::new() }
+
+#[test]
+fn example1() {
+	let block = BlockBuilder::new().header().time(1000).build().build();
+	assert_eq!(block.header().time, 1000);
+}
+
+#[test]
+fn example2() {
+	let block = BlockBuilder::new()
+		.header().build()
+		.transaction().lock_time(100500).build()
+		.build();
+
+	assert_eq!(block.transactions().len(), 1);
+}
+
+#[test]
+fn example3() {
+	let block = block_builder().header().build()
+		.transaction().coinbase().build()
+		.build();
+
+	assert!(block.transactions()[0].is_coinbase());
+}
+
+#[test]
+fn example4() {
+	let block = block_builder().header().build()
+		.transaction().coinbase()
+			.output().value(10).build()
+			.build()
+		.transaction()
+			.input().hash(H256::from(1)).index(1).build()
+			.build()
+		.build();
+
+	assert_eq!(block.transactions().len(), 2);
+	assert_eq!(block.transactions()[1].inputs[0].previous_output.hash, H256::from(1));
+}
diff --git a/test-data/src/invoke.rs b/test-data/src/invoke.rs
new file mode 100644
index 00000000..4223dc58
--- /dev/null
+++ b/test-data/src/invoke.rs
@@ -0,0 +1,15 @@
+//! invoke helper
+
+pub trait Invoke<A> {
+	type Result;
+
+	fn invoke(self, arg: A) -> Self::Result;
+}
+
+pub struct Identity;
+
+impl<A> Invoke<A> for Identity {
+	type Result = A;
+
+	fn invoke(self, arg: A) -> A { arg }
+}
diff --git a/test-data/src/lib.rs b/test-data/src/lib.rs
index 3c347d29..a3236e17 100644
--- a/test-data/src/lib.rs
+++ b/test-data/src/lib.rs
@@ -7,8 +7,11 @@ extern crate serialization as ser;
 use chain::Block;
 
 pub mod chain_builder;
+pub mod block;
+pub mod invoke;
 
 pub use chain_builder::{ChainBuilder, TransactionBuilder};
+pub use block::block_builder;
 
 pub fn block1() -> Block {
 	let block: Block = "01000000ba8b9cda965dd8e536670f9ddec10e53aab14b20bacad27b9137190000000000190760b278fe7b8565fda3b968b918d5fd997f993b23674c0af3b6fde300b38f33a5914ce6ed5b1b01e32f570201000000010000000000000000000000000000000000000000000000000000000000000000ffffffff0704e6ed5b1b014effffffff0100f2052a01000000434104b68a50eaa0287eff855189f949c1c6e5f58b37c88231373d8a59809cbae83059cc6469d65c665ccfd1cfeb75c6e8e19413bba7fbff9bc762419a76d87b16086eac000000000100000001a6b97044d03da79c005b20ea9c0e1a6d9dc12d9f7b91a5911c9030a439eed8f5000000004948304502206e21798a42fae0e854281abd38bacd1aeed3ee3738d9e1446618c4571d1090db022100e2ac980643b0b82c0e88ffdfec6b64e3e6ba35e7ba5fdd7d5d6cc8d25c6b241501ffffffff0100f2052a010000001976a914404371705fa9bd789a2fcd52d2c580b65d35549d88ac00000000".into();