diff --git a/ethcore/Cargo.toml b/ethcore/Cargo.toml
index 71c84a293f9..2b6ab9ebc3a 100644
--- a/ethcore/Cargo.toml
+++ b/ethcore/Cargo.toml
@@ -89,3 +89,5 @@ json-tests = ["ethcore-transaction/json-tests"]
 test-heavy = []
 # Compile benches
 benches = []
+# Compile test helpers
+test-helpers = []
diff --git a/ethcore/private-tx/Cargo.toml b/ethcore/private-tx/Cargo.toml
index 0fa11aec84b..0ca8ab8acdd 100644
--- a/ethcore/private-tx/Cargo.toml
+++ b/ethcore/private-tx/Cargo.toml
@@ -35,3 +35,6 @@ serde_derive = "1.0"
 serde_json = "1.0"
 tiny-keccak = "1.3"
 url = "1"
+
+[dev-dependencies]
+ethcore = { path = "..", features = ["test-helpers"] }
diff --git a/ethcore/src/client/mod.rs b/ethcore/src/client/mod.rs
index 4c410d30117..ff7fb8f692f 100644
--- a/ethcore/src/client/mod.rs
+++ b/ethcore/src/client/mod.rs
@@ -20,16 +20,20 @@ mod ancient_import;
 mod client;
 mod config;
 mod error;
+#[cfg(any(test, feature="test-helpers"))]
 mod evm_test_client;
 mod io_message;
+#[cfg(any(test, feature="test-helpers"))]
 mod test_client;
 mod trace;
 
 pub use self::client::*;
 pub use self::config::{Mode, ClientConfig, DatabaseCompactionProfile, BlockChainConfig, VMType};
 pub use self::error::Error;
+#[cfg(any(test, feature="test-helpers"))]
 pub use self::evm_test_client::{EvmTestClient, EvmTestError, TransactResult};
 pub use self::io_message::ClientIoMessage;
+#[cfg(any(test, feature="test-helpers"))]
 pub use self::test_client::{TestBlockChainClient, EachBlockWith};
 pub use self::chain_notify::{ChainNotify, ChainRoute, ChainRouteType, ChainMessageType};
 pub use self::traits::{
diff --git a/ethcore/src/lib.rs b/ethcore/src/lib.rs
index b1782cb1d6c..3929b8dec79 100644
--- a/ethcore/src/lib.rs
+++ b/ethcore/src/lib.rs
@@ -157,8 +157,6 @@ pub mod snapshot;
 pub mod spec;
 pub mod state;
 pub mod state_db;
-// Test helpers made public for usage outside ethcore
-pub mod test_helpers;
 pub mod trace;
 pub mod verification;
 
@@ -177,6 +175,8 @@ mod tests;
 #[cfg(test)]
 #[cfg(feature="json-tests")]
 mod json_tests;
+#[cfg(any(test, feature="test-helpers"))]
+pub mod test_helpers;
 #[cfg(test)]
 mod test_helpers_internal;
 
diff --git a/ethcore/src/spec/spec.rs b/ethcore/src/spec/spec.rs
index 98720647d8f..1a022336f4a 100644
--- a/ethcore/src/spec/spec.rs
+++ b/ethcore/src/spec/spec.rs
@@ -516,6 +516,7 @@ macro_rules! load_bundled {
 	};
 }
 
+#[cfg(any(test, feature="test-helpers"))]
 macro_rules! load_machine_bundled {
 	($e:expr) => {
 		Spec::load_machine(
@@ -839,39 +840,44 @@ impl Spec {
 		self.engine.genesis_epoch_data(&genesis, &call)
 	}
 
+	/// Create a new Spec with InstantSeal consensus which does internal sealing (not requiring
+	/// work).
+	pub fn new_instant() -> Spec {
+		load_bundled!("instant_seal")
+	}
+
 	/// Create a new Spec which conforms to the Frontier-era Morden chain except that it's a
 	/// NullEngine consensus.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test() -> Spec {
 		load_bundled!("null_morden")
 	}
 
 	/// Create the EthereumMachine corresponding to Spec::new_test.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_machine() -> EthereumMachine { load_machine_bundled!("null_morden") }
 
-
 	/// Create a new Spec which conforms to the Frontier-era Morden chain except that it's a NullEngine consensus with applying reward on block close.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_with_reward() -> Spec { load_bundled!("null_morden_with_reward") }
 
 	/// Create a new Spec which is a NullEngine consensus with a premine of address whose
 	/// secret is keccak('').
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_null() -> Spec {
 		load_bundled!("null")
 	}
 
 	/// Create a new Spec which constructs a contract at address 5 with storage at 0 equal to 1.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_constructor() -> Spec {
 		load_bundled!("constructor")
 	}
 
-	/// Create a new Spec with InstantSeal consensus which does internal sealing (not requiring
-	/// work).
-	pub fn new_instant() -> Spec {
-		load_bundled!("instant_seal")
-	}
-
 	/// Create a new Spec with AuthorityRound consensus which does internal sealing (not
 	/// requiring work).
 	/// Accounts with secrets keccak("0") and keccak("1") are the validators.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_round() -> Self {
 		load_bundled!("authority_round")
 	}
@@ -879,6 +885,7 @@ impl Spec {
 	/// Create a new Spec with AuthorityRound consensus which does internal sealing (not
 	/// requiring work) with empty step messages enabled.
 	/// Accounts with secrets keccak("0") and keccak("1") are the validators.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_round_empty_steps() -> Self {
 		load_bundled!("authority_round_empty_steps")
 	}
@@ -886,6 +893,7 @@ impl Spec {
 	/// Create a new Spec with AuthorityRound consensus (with empty steps) using a block reward
 	/// contract. The contract source code can be found at:
 	/// https://github.com/parity-contracts/block-reward/blob/daf7d44383b6cdb11cb6b953b018648e2b027cfb/contracts/ExampleBlockReward.sol
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_round_block_reward_contract() -> Self {
 		load_bundled!("authority_round_block_reward_contract")
 	}
@@ -893,6 +901,7 @@ impl Spec {
 	/// Create a new Spec with Tendermint consensus which does internal sealing (not requiring
 	/// work).
 	/// Account keccak("0") and keccak("1") are a authorities.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_test_tendermint() -> Self {
 		load_bundled!("tendermint")
 	}
@@ -905,6 +914,7 @@ impl Spec {
 	/// "0xbfc708a000000000000000000000000082a978b3f5962a5b0957d9ee9eef472ee55b42f1" and added
 	/// back in using
 	/// "0x4d238c8e00000000000000000000000082a978b3f5962a5b0957d9ee9eef472ee55b42f1".
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_validator_safe_contract() -> Self {
 		load_bundled!("validator_safe_contract")
 	}
@@ -912,6 +922,7 @@ impl Spec {
 	/// The same as the `safeContract`, but allows reporting and uses AuthorityRound.
 	/// Account is marked with `reportBenign` it can be checked as disliked with "0xd8f2e0bf".
 	/// Validator can be removed with `reportMalicious`.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_validator_contract() -> Self {
 		load_bundled!("validator_contract")
 	}
@@ -920,6 +931,7 @@ impl Spec {
 	/// height.
 	/// Account with secrets keccak("0") is the validator for block 1 and with keccak("1")
 	/// onwards.
+	#[cfg(any(test, feature="test-helpers"))]
 	pub fn new_validator_multi() -> Self {
 		load_bundled!("validator_multi")
 	}
diff --git a/ethcore/sync/Cargo.toml b/ethcore/sync/Cargo.toml
index cf163cc7bd5..66ee5662158 100644
--- a/ethcore/sync/Cargo.toml
+++ b/ethcore/sync/Cargo.toml
@@ -38,3 +38,4 @@ ethcore-io = { path = "../../util/io", features = ["mio"] }
 ethkey = { path = "../../ethkey" }
 kvdb-memorydb = { path = "../../util/kvdb-memorydb" }
 ethcore-private-tx = { path = "../private-tx" }
+ethcore = { path = "..", features = ["test-helpers"] }