diff --git a/test-data/src/block.rs b/test-data/src/block.rs
new file mode 100644
index 00000000..341c6dff
--- /dev/null
+++ b/test-data/src/block.rs
@@ -0,0 +1,204 @@
+//! Block builder
+
+use chain;
+use primitives::hash::H256;
+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(),
+		}
+	}
+
+	pub fn lock_time(mut self, time: u32) -> Self {
+		self.lock_time = time;
+		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,
+			}
+		)
+	}
+}
+
+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);
+}
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 = "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".into();