diff --git a/substrate/native-runtime/support/src/lib.rs b/substrate/native-runtime/support/src/lib.rs
index 93947dde68..7bbd6d235e 100644
--- a/substrate/native-runtime/support/src/lib.rs
+++ b/substrate/native-runtime/support/src/lib.rs
@@ -8,7 +8,7 @@ pub use std::cell::RefCell;
 pub use std::boxed::Box;
 pub use std::mem::{size_of, transmute};
 
-use polkadot_state_machine::Externalities;
+pub use polkadot_state_machine::Externalities;
 use std::fmt;
 
 // TODO: use the real error, not NoError.
diff --git a/substrate/wasm-runtime/polkadot/src/lib.rs b/substrate/wasm-runtime/polkadot/src/lib.rs
index fb8e5b86f8..205d2e31a7 100644
--- a/substrate/wasm-runtime/polkadot/src/lib.rs
+++ b/substrate/wasm-runtime/polkadot/src/lib.rs
@@ -3,7 +3,7 @@
 
 #[macro_use]
 extern crate runtime_support;
-use runtime_support::{set_storage, storage, storage_into, Vec, size_of};
+use runtime_support::{Vec, size_of};
 use runtime_support::{Rc, RefCell, transmute, Box};
 
 /// The hash of an ECDSA pub key which is used to identify an external transactor.
@@ -93,6 +93,12 @@ struct Environment {
 	block_number: BlockNumber,
 }
 
+fn with_env<T, F: FnOnce(&mut Environment) -> T>(f: F) -> T {
+	let e = env();
+	let mut eb = e.borrow_mut();
+	f(&mut *eb)
+}
+
 fn env() -> Rc<RefCell<Environment>> {
 	// Initialize it to a null value
 	static mut SINGLETON: *const Rc<RefCell<Environment>> = 0 as *const Rc<RefCell<Environment>>;
@@ -111,6 +117,77 @@ fn env() -> Rc<RefCell<Environment>> {
 	}
 }
 
+fn value_vec(mut value: u32, initial: Vec<u8>) -> Vec<u8> {
+	let mut acc = initial;
+	while value > 0 {
+		acc.push(value as u8);
+		value /= 256;
+	}
+	acc
+}
+
+trait EndianSensitive: Sized {
+	fn to_le(self) -> Self { self }
+	fn to_be(self) -> Self { self }
+	fn from_le(self) -> Self { self }
+	fn from_be(self) -> Self { self }
+}
+
+macro_rules! impl_endians {
+	( $( $t:ty ),* ) => { $(
+		impl EndianSensitive for $t {
+			fn to_le(self) -> Self { <$t>::to_le(self) }
+			fn to_be(self) -> Self { <$t>::to_be(self) }
+			fn from_le(self) -> Self { <$t>::from_le(self) }
+			fn from_be(self) -> Self { <$t>::from_be(self) }
+		}
+	)* }
+}
+macro_rules! impl_non_endians {
+	( $( $t:ty ),* ) => { $(
+		impl EndianSensitive for $t {}
+	)* }
+}
+
+impl_endians!(u8, u16, u32, u64, usize, i8, i16, i32, i64, isize);
+impl_non_endians!([u8; 20], [u8; 32]);
+
+trait Storage {
+	fn storage_into(key: &[u8]) -> Self;
+	fn store(self, key: &[u8]);
+}
+
+impl<T: Default + EndianSensitive> Storage for T {
+	fn storage_into(key: &[u8]) -> Self {
+		runtime_support::storage_into(key).map(EndianSensitive::from_le).unwrap_or_else(Default::default)
+	}
+
+	fn store(self, key: &[u8]) {
+		let size = size_of::<Self>();
+		let value_bytes = self.to_le();
+		let value_slice = unsafe {
+			std::slice::from_raw_parts(transmute::<*const Self, *const u8>(&value_bytes), size)
+		};
+		runtime_support::set_storage(key, value_slice);
+	}
+}
+
+fn storage_into<T: Storage>(key: &[u8]) -> T {
+	T::storage_into(key)
+}
+
+
+trait KeyedVec {
+	fn to_keyed_vec(&self, prepend_key: &[u8]) -> Vec<u8>;
+}
+impl KeyedVec for AccountID {
+	fn to_keyed_vec(&self, prepend_key: &[u8]) -> Vec<u8> {
+		let mut r = prepend_key.to_vec();
+		r.extend_from_slice(self);
+		r
+	}
+}
+
 // TODO: include RLP implementation
 // TODO: add keccak256 (or some better hashing scheme) & ECDSA-recover (or some better sig scheme)
 
@@ -127,26 +204,27 @@ pub fn execute_transaction(_input: Vec<u8>) -> Vec<u8> {
 impl_stubs!(execute_block, execute_transaction);
 
 /// The current relay chain identifier.
-fn chain_id() -> ChainID {
+pub fn chain_id() -> ChainID {
 	// TODO: retrieve from external
 	unimplemented!()
 }
 
-mod environment {
+pub mod environment {
 	use super::*;
 
 	/// The current block number being processed. Set by `execute_block`.
-	pub fn block_number() -> BlockNumber { let e = env(); let eb = e.borrow(); eb.block_number }
+	pub fn block_number() -> BlockNumber {
+		with_env(|e| e.block_number)
+	}
 
 	/// Get the block hash of a given block.
-	pub fn block_hash(_number: BlockNumber) -> Hash { unimplemented!() }
+	pub fn block_hash(_number: BlockNumber) -> Hash {
+		unimplemented!()
+	}
 
 	pub fn execute_block(_block: &Block) -> Vec<u8> {
 		// populate environment from header.
-		{
-			let e = env();
-			e.borrow_mut().block_number = _block.header.number;
-		}
+		with_env(|e| e.block_number = _block.header.number);
 
 		staking::pre_transactions();
 
@@ -174,7 +252,7 @@ mod environment {
 
 	/// Set the new code.
 	pub fn set_code(new: &[u8]) {
-		set_storage(b"\0code", new)
+		runtime_support::set_storage(b"\0code", new)
 	}
 
 	/// Set the light-client digest for the header.
@@ -184,33 +262,24 @@ mod environment {
 	}
 }
 
-mod consensus {
+pub mod consensus {
 	use super::*;
 
-	fn value_vec(mut value: usize, initial: Vec<u8>) -> Vec<u8> {
-		let mut acc = initial;
-		while value > 0 {
-			acc.push(value as u8);
-			value /= 256;
-		}
-		acc
+	pub fn set_authority(index: u32, authority: AccountID) {
+		runtime_support::set_storage(&value_vec(index, b"\0authority".to_vec()), &authority[..]);
 	}
 
-	fn set_authority(index: usize, authority: AccountID) {
-		set_storage(&value_vec(index, b"\0authority".to_vec()), &authority[..]);
+	fn authority(index: u32) -> AccountID {
+		runtime_support::storage_into(&value_vec(index, b"\0authority".to_vec())).unwrap()
 	}
 
-	fn authority(index: usize) -> AccountID {
-		storage_into(&value_vec(index, b"\0authority".to_vec())).unwrap()
-	}
-
-	fn set_authority_count(count: usize) {
+	pub fn set_authority_count(count: u32) {
 		(count..authority_count()).for_each(|i| set_authority(i, SessionKey::default()));
-		set_storage(b"\0authority_count", &value_vec(count, Vec::new()));
+		runtime_support::set_storage(b"\0authority_count", &value_vec(count, Vec::new()));
 	}
 
-	fn authority_count() -> usize {
-		storage(b"\0authority_count").into_iter().rev().fold(0, |acc, i| (acc << 8) + (i as usize))
+	fn authority_count() -> u32 {
+		runtime_support::storage(b"\0authority_count").into_iter().rev().fold(0, |acc, i| (acc << 8) + (i as u32))
 	}
 
 	/// Get the current set of authorities. These are the session keys.
@@ -221,9 +290,9 @@ mod consensus {
 	/// Set the current set of authorities' session keys.
 	///
 	/// Called by `next_session` only.
-	fn set_authorities(authorities: &[AccountID]) {
-		set_authority_count(authorities.len());
-		authorities.iter().enumerate().for_each(|(v, &i)| set_authority(v, i));
+	pub fn set_authorities(authorities: &[AccountID]) {
+		set_authority_count(authorities.len() as u32);
+		authorities.iter().enumerate().for_each(|(v, &i)| set_authority(v as u32, i));
 	}
 
 	/// Get the current set of validators. These are the long-term identifiers for the validators
@@ -265,35 +334,56 @@ mod consensus {
 	}
 }
 
-mod staking {
+pub mod staking {
 	use super::*;
 
 	/// The length of a staking era in blocks.
-	pub fn era_length() -> BlockNumber { sessions_per_era() * consensus::session_length() }
+	pub fn era_length() -> BlockNumber {
+		sessions_per_era() * consensus::session_length()
+	}
 
 	/// The length of a staking era in sessions.
-	pub fn sessions_per_era() -> BlockNumber { 10 }
+	pub fn sessions_per_era() -> BlockNumber {
+		10
+	}
 
 	/// The era has changed - enact new staking set.
 	///
 	/// NOTE: This always happens on a session change.
-	fn next_era() { unimplemented!() }
+	pub fn next_era() {
+		unimplemented!()
+	}
 
 	/// The balance of a given account.
-	fn balance(_who: AccountID) -> Balance { unimplemented!() }
+	pub fn balance(who: &AccountID) -> Balance {
+		storage_into(&who.to_keyed_vec(b"sta\0bal\0"))
+	}
 
 	/// Transfer some unlocked staking balance to another staker.
-	pub fn transfer_stake(_transactor: AccountID, _dest: AccountID, _value: Balance) { unimplemented!() }
+	pub fn transfer_stake(transactor: &AccountID, dest: &AccountID, value: Balance) {
+		let from_key = transactor.to_keyed_vec(b"sta\0bal\0");
+		let from_balance: Balance = storage_into(&from_key);
+		assert!(from_balance >= value);
+		let to_key = dest.to_keyed_vec(b"sta\0bal\0");
+		let to_balance: Balance = storage_into(&to_key);
+		assert!(to_balance + value > to_balance);	// no overflow
+		(from_balance - value).store(&from_key);
+		(to_balance + value).store(&to_key);
+	}
 
 	/// Declare the desire to stake for the transactor.
 	///
 	/// Effects will be felt at the beginning of the next era.
-	pub fn stake(_transactor: &AccountID) { unimplemented!() }
+	pub fn stake(_transactor: &AccountID) {
+		unimplemented!()
+	}
 
 	/// Retract the desire to stake for the transactor.
 	///
 	/// Effects will be felt at the beginning of the next era.
-	pub fn unstake(_transactor: &AccountID) { unimplemented!() }
+	pub fn unstake(_transactor: &AccountID) {
+		unimplemented!()
+	}
 
 	/// Hook to be called prior to transaction processing.
 	pub fn pre_transactions() {
@@ -307,17 +397,92 @@ mod staking {
 	}
 }
 
-mod authentication {
+pub mod authentication {
 	use super::*;
 
-	fn validate_signature(_tx: Transaction) -> ( AccountID, TxOrder ) { unimplemented!() }
-	fn nonce(_id: AccountID) -> TxOrder { unimplemented!() }
-	fn authenticate(_tx: Transaction) -> AccountID { unimplemented!() }
+	pub fn validate_signature(_tx: Transaction) -> ( AccountID, TxOrder ) {
+		unimplemented!()
+	}
+
+	pub fn nonce(_id: AccountID) -> TxOrder {
+		unimplemented!()
+	}
+
+	pub fn authenticate(_tx: Transaction) -> AccountID {
+		unimplemented!()
+	}
 }
 
-mod timestamp {
+pub mod timestamp {
 	use super::*;
 
-	fn timestamp() -> Timestamp { unimplemented!() }
-	fn set_timestamp(_now: Timestamp) { unimplemented!() }
+	pub fn timestamp() -> Timestamp {
+		unimplemented!()
+	}
+
+	pub fn set_timestamp(_now: Timestamp) {
+		unimplemented!()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+
+	use super::*;
+
+	use std::collections::HashMap;
+	use runtime_support::{NoError, with_externalities, Externalities};
+
+	#[derive(Debug, Default)]
+	struct TestExternalities {
+		storage: HashMap<Vec<u8>, Vec<u8>>,
+	}
+	impl Externalities for TestExternalities {
+		type Error = NoError;
+
+		fn storage(&self, key: &[u8]) -> Result<&[u8], NoError> {
+			Ok(self.storage.get(&key.to_vec()).map_or(&[] as &[u8], Vec::as_slice))
+		}
+
+		fn set_storage(&mut self, key: Vec<u8>, value: Vec<u8>) {
+			self.storage.insert(key, value);
+		}
+	}
+
+	macro_rules! map {
+		($( $name:expr => $value:expr ),*) => (
+			vec![ $( ( $name, $value ) ),* ].into_iter().collect()
+		)
+	}
+
+	#[test]
+	fn staking_balance_works() {
+		let one: AccountID = [1u8; 32];
+		let two: AccountID = [2u8; 32];
+
+		let mut t = TestExternalities { storage: map![
+			{ let mut r = b"sta\0bal\0".to_vec(); r.extend_from_slice(&one); r } => vec![42u8, 0, 0, 0, 0, 0, 0, 0]
+		], };
+
+		with_externalities(&mut t, || {
+			assert_eq!(staking::balance(&one), 42);
+			assert_eq!(staking::balance(&two), 0);
+		});
+	}
+
+	#[test]
+	fn staking_balance_transfer_works() {
+		let one: AccountID = [1u8; 32];
+		let two: AccountID = [2u8; 32];
+
+		let mut t = TestExternalities { storage: map![
+			{ let mut r = b"sta\0bal\0".to_vec(); r.extend_from_slice(&one); r } => vec![111u8, 0, 0, 0, 0, 0, 0, 0]
+		], };
+
+		with_externalities(&mut t, || {
+			staking::transfer_stake(&one, &two, 69);
+			assert_eq!(staking::balance(&one), 42);
+			assert_eq!(staking::balance(&two), 69);
+		});
+	}
 }