diff --git a/db/Cargo.toml b/db/Cargo.toml
index 9962bc54..800fdc32 100644
--- a/db/Cargo.toml
+++ b/db/Cargo.toml
@@ -13,3 +13,6 @@ chain = { path = "../chain"  }
 serialization = { path = "../serialization" }
 parking_lot = "0.3"
 test-data = { path = "../test-data" }
+
+[features]
+dev = []
diff --git a/db/src/lib.rs b/db/src/lib.rs
index dc826523..8b892a20 100644
--- a/db/src/lib.rs
+++ b/db/src/lib.rs
@@ -15,6 +15,8 @@ extern crate test_data;
 
 mod kvdb;
 mod storage;
+#[cfg(feature="dev")]
+mod test_storage;
 
 pub enum BlockRef {
 	Number(u64),
@@ -23,3 +25,6 @@ pub enum BlockRef {
 
 pub use storage::{Storage, Store, Error};
 pub use kvdb::Database;
+
+#[cfg(feature="dev")]
+pub use test_storage::TestStorage;
diff --git a/db/src/test_storage.rs b/db/src/test_storage.rs
new file mode 100644
index 00000000..b62c27bd
--- /dev/null
+++ b/db/src/test_storage.rs
@@ -0,0 +1,78 @@
+//! Test storage
+
+use super::{BlockRef, Store, Error};
+use chain;
+use primitives::hash::H256;
+use serialization;
+use chain::bytes::Bytes;
+use std::collections::HashMap;
+
+#[derive(Default)]
+pub struct TestStorage {
+	blocks: HashMap<H256, chain::Block>,
+	heights: HashMap<usize, H256>,
+}
+
+impl TestStorage {
+	fn resolve_hash(&self, block_ref: BlockRef) -> Option<H256> {
+		match block_ref {
+			BlockRef::Number(n) => self.block_hash(n),
+			BlockRef::Hash(h) => Some(h),
+		}
+	}
+
+	pub fn with_blocks(blocks: &[chain::Block]) -> Self {
+		let mut storage = TestStorage::default();
+		for (idx, block) in blocks.iter().enumerate() {
+			let hash = block.hash();
+			storage.blocks.insert(hash.clone(), block.clone());
+			storage.heights.insert(idx, hash);
+		}
+		storage
+	}
+}
+
+impl Store for TestStorage {
+	fn block_hash(&self, number: u64) -> Option<H256> {
+		self.heights.get(&(number as usize)).cloned()
+	}
+
+	fn block_header_bytes(&self, block_ref: BlockRef) -> Option<Bytes> {
+		self.resolve_hash(block_ref)
+			.and_then(|ref h| self.blocks.get(h))
+			.map(|ref block| serialization::serialize(block.header()))
+	}
+
+	fn block_transaction_hashes(&self, block_ref: BlockRef) -> Vec<H256> {
+		self.resolve_hash(block_ref)
+			.and_then(|ref h| self.blocks.get(h))
+			.map(|ref block| block.transactions().iter().map(|tx| tx.hash()).collect())
+			.unwrap_or(Vec::new())
+	}
+
+	fn transaction_bytes(&self, hash: &H256) -> Option<Bytes> {
+		self.transaction(hash).map(|tx| serialization::serialize(&tx))
+	}
+
+	fn transaction(&self, hash: &H256) -> Option<chain::Transaction> {
+		self.blocks.iter().flat_map(|(_, b)| b.transactions())
+			.find(|ref tx| tx.hash() == *hash)
+			.cloned()
+	}
+
+	fn block_transactions(&self, block_ref: BlockRef) -> Vec<chain::Transaction> {
+		self.block(block_ref)
+			.map(|b| b.transactions().iter().cloned().collect())
+			.unwrap_or(Vec::new())
+	}
+
+	fn block(&self, block_ref: BlockRef) -> Option<chain::Block> {
+		self.resolve_hash(block_ref)
+			.and_then(|ref h| self.blocks.get(h))
+			.cloned()
+	}
+
+	fn insert_block(&self, _block: &chain::Block) -> Result<(), Error> {
+		Ok(())
+	}
+}
diff --git a/verification/Cargo.toml b/verification/Cargo.toml
index 363785b7..e98c7782 100644
--- a/verification/Cargo.toml
+++ b/verification/Cargo.toml
@@ -4,7 +4,6 @@ version = "0.1.0"
 authors = ["Nikolay Volf <nikvolf@gmail.com>"]
 
 [dependencies]
-db = { path = "../db" }
 ethcore-devtools = { path = "../devtools" }
 primitives = { path = "../primitives" }
 chain = { path = "../chain"  }
@@ -15,3 +14,7 @@ test-data = { path = "../test-data" }
 byteorder = "0.5"
 time = "0.1"
 script = { path = "../script" }
+
+[dependencies.db]
+path = "../db"
+features = ["dev"]
diff --git a/verification/src/chain_verifier.rs b/verification/src/chain_verifier.rs
index cb6367fb..7e927252 100644
--- a/verification/src/chain_verifier.rs
+++ b/verification/src/chain_verifier.rs
@@ -106,85 +106,10 @@ mod tests {
 
 	use super::ChainVerifier;
 	use super::super::{Verify, Chain};
-	use primitives::hash::H256;
-	use chain;
-	use std::collections::HashMap;
-	use db::{self, BlockRef, Store};
-	use serialization;
-	use serialization::bytes::Bytes;
+	use db::TestStorage;
 	use test_data;
 	use std::sync::Arc;
 
-	#[derive(Default)]
-	struct TestStorage {
-		blocks: HashMap<H256, chain::Block>,
-		heights: HashMap<usize, H256>,
-	}
-
-	impl TestStorage {
-		fn resolve_hash(&self, block_ref: BlockRef) -> Option<H256> {
-			match block_ref {
-				BlockRef::Number(n) => self.block_hash(n),
-				BlockRef::Hash(h) => Some(h),
-			}
-		}
-
-		fn with_blocks(blocks: &[chain::Block]) -> Self {
-			let mut storage = TestStorage::default();
-			for (idx, block) in blocks.iter().enumerate() {
-				let hash = block.hash();
-				storage.blocks.insert(hash.clone(), block.clone());
-				storage.heights.insert(idx, hash);
-			}
-			storage
-		}
-	}
-
-	impl Store for TestStorage {
-		fn block_hash(&self, number: u64) -> Option<H256> {
-			self.heights.get(&(number as usize)).cloned()
-		}
-
-		fn block_header_bytes(&self, block_ref: BlockRef) -> Option<Bytes> {
-			self.resolve_hash(block_ref)
-				.and_then(|ref h| self.blocks.get(h))
-				.map(|ref block| serialization::serialize(block.header()))
-		}
-
-		fn block_transaction_hashes(&self, block_ref: BlockRef) -> Vec<H256> {
-			self.resolve_hash(block_ref)
-				.and_then(|ref h| self.blocks.get(h))
-				.map(|ref block| block.transactions().iter().map(|tx| tx.hash()).collect())
-				.unwrap_or(Vec::new())
-		}
-
-		fn transaction_bytes(&self, hash: &H256) -> Option<Bytes> {
-			self.transaction(hash).map(|tx| serialization::serialize(&tx))
-		}
-
-		fn transaction(&self, hash: &H256) -> Option<chain::Transaction> {
-			self.blocks.iter().flat_map(|(_, b)| b.transactions())
-				.find(|ref tx| tx.hash() == *hash)
-				.cloned()
-		}
-
-		fn block_transactions(&self, block_ref: BlockRef) -> Vec<chain::Transaction> {
-			self.block(block_ref)
-				.map(|b| b.transactions().iter().cloned().collect())
-				.unwrap_or(Vec::new())
-		}
-
-		fn block(&self, block_ref: BlockRef) -> Option<chain::Block> {
-			self.resolve_hash(block_ref)
-				.and_then(|ref h| self.blocks.get(h))
-				.cloned()
-		}
-
-		fn insert_block(&self, _block: &chain::Block) -> Result<(), db::Error> {
-			Ok(())
-		}
-	}
-
 	#[test]
 	fn verify_orphan() {
 		let storage = TestStorage::with_blocks(&vec![test_data::genesis()]);