Add revert variables, change lib => libs to get around gitignore

21 files changed, 325 insertions, 52 deletions

diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
index 14d5eb7ca..308dace32 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -20,7 +20,7 @@ pragma solidity ^0.4.23;
 
 import "../../utils/Ownable/Ownable.sol";
 import "../AssetProxy/interfaces/IAssetProxy.sol";
-import "./lib/LibExchangeErrors.sol";
+import "./libs/LibExchangeErrors.sol";
 import "./mixins/MAssetProxyDispatcher.sol";
 
 contract MixinAssetProxyDispatcher is
@@ -94,7 +94,7 @@ contract MixinAssetProxyDispatcher is
             // Lookup asset proxy
             require(
                 assetMetadata.length >= 1,
-                GREATER_THAN_ZERO_LENGTH_REQUIRED
+                GT_ZERO_LENGTH_REQUIRED
             );
             uint8 assetProxyId = uint8(assetMetadata[0]);
             IAssetProxy assetProxy = assetProxies[assetProxyId];
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
index c22acf966..82c7a2ddc 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
@@ -19,10 +19,10 @@
 pragma solidity ^0.4.23;
 pragma experimental ABIEncoderV2;
 
-import "./lib/LibFillResults.sol";
-import "./lib/LibOrder.sol";
-import "./lib/LibMath.sol";
-import "./lib/LibExchangeErrors.sol";
+import "./libs/LibFillResults.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibMath.sol";
+import "./libs/LibExchangeErrors.sol";
 import "./mixins/MExchangeCore.sol";
 import "./mixins/MSettlement.sol";
 import "./mixins/MSignatureValidator.sol";
@@ -94,11 +94,11 @@ contract MixinExchangeCore is
         if (filled[orderHash] == 0) {
             require(
                 order.makerAssetAmount > 0,
-                GREATER_THAN_ZERO_AMOUNT_REQUIRED
+                GT_ZERO_AMOUNT_REQUIRED
             );
             require(
                 order.takerAssetAmount > 0,
-                GREATER_THAN_ZERO_AMOUNT_REQUIRED
+                GT_ZERO_AMOUNT_REQUIRED
             );
             require(
                 isValidSignature(orderHash, order.makerAddress, signature),
@@ -124,7 +124,7 @@ contract MixinExchangeCore is
         }
         require(
             takerAssetFillAmount > 0,
-            GREATER_THAN_ZERO_AMOUNT_REQUIRED
+            GT_ZERO_AMOUNT_REQUIRED
         );
 
         // Validate order expiration
@@ -174,11 +174,11 @@ contract MixinExchangeCore is
         // Validate the order
         require(
             order.makerAssetAmount > 0,
-            GREATER_THAN_ZERO_AMOUNT_REQUIRED
+            GT_ZERO_AMOUNT_REQUIRED
         );
         require(
             order.takerAssetAmount > 0,
-            GREATER_THAN_ZERO_AMOUNT_REQUIRED
+            GT_ZERO_AMOUNT_REQUIRED
         );
 
         // Validate sender is allowed to cancel this order
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol
index ae1dd9bee..30f1bb49b 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSettlement.sol
@@ -20,15 +20,17 @@ pragma solidity ^0.4.23;
 
 import "./mixins/MSettlement.sol";
 import "./mixins/MAssetProxyDispatcher.sol";
-import "./lib/LibOrder.sol";
-import "./lib/LibMath.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibMath.sol";
 
 contract MixinSettlement is
     LibMath,
     MSettlement,
     MAssetProxyDispatcher
 {
-    /// ZRX metadata used for fee transfers.
+    // ZRX metadata used for fee transfers.
+    // This will be constant throughout the life of the Exchange contract,
+    // since ZRX will always be transferred via the ERC20 AssetProxy.
     bytes internal ZRX_PROXY_DATA;
 
     /// @dev Gets the ZRX metadata used for fee transfers.
@@ -49,10 +51,10 @@ contract MixinSettlement is
         ZRX_PROXY_DATA = _zrxProxyData;
     }
 
-    /// @dev Settles an order by transfering assets between counterparties.
+    /// @dev Settles an order by transferring assets between counterparties.
     /// @param order Order struct containing order specifications.
     /// @param takerAddress Address selling takerAsset and buying makerAsset.
-    /// @param takerAssetFilledAmount The amount of takerAsset that will be transfered to the order's maker.
+    /// @param takerAssetFilledAmount The amount of takerAsset that will be transferred to the order's maker.
     /// @return Amount filled by maker and fees paid by maker/taker.
     function settleOrder(
         LibOrder.Order memory order,
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
index 43d138669..2322625d9 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
@@ -20,7 +20,7 @@ pragma solidity ^0.4.23;
 
 import "./mixins/MSignatureValidator.sol";
 import "./interfaces/ISigner.sol";
-import "./lib/LibExchangeErrors.sol";
+import "./libs/LibExchangeErrors.sol";
 import "../../utils/LibBytes/LibBytes.sol";
 
 contract MixinSignatureValidator is
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
index a8b60e8a4..7f12834a3 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
@@ -19,7 +19,7 @@ pragma solidity ^0.4.21;
 
 import "./mixins/MSignatureValidator.sol";
 import "./mixins/MTransactions.sol";
-import "./lib/LibExchangeErrors.sol";
+import "./libs/LibExchangeErrors.sol";
 
 contract MixinTransactions is
     LibExchangeErrors,
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
index 33a125083..42517221e 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
@@ -21,10 +21,10 @@ pragma experimental ABIEncoderV2;
 
 import "../../utils/LibBytes/LibBytes.sol";
 import "./mixins/MExchangeCore.sol";
-import "./lib/LibMath.sol";
-import "./lib/LibOrder.sol";
-import "./lib/LibFillResults.sol";
-import "./lib/LibExchangeErrors.sol";
+import "./libs/LibMath.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibFillResults.sol";
+import "./libs/LibExchangeErrors.sol";
 
 contract MixinWrapperFunctions is
     LibOrder,
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
index d60b8ca48..4e4ed6be8 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
@@ -38,4 +38,4 @@ contract IAssetProxyDispatcher {
         external
         view
         returns (address);
-}
\ No newline at end of file
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchangeCore.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchangeCore.sol
index 18f794ee8..0f19525ca 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchangeCore.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchangeCore.sol
@@ -19,8 +19,8 @@
 pragma solidity ^0.4.23;
 pragma experimental ABIEncoderV2;
 
-import "../lib/LibOrder.sol";
-import "../lib/LibFillResults.sol";
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
 
 contract IExchangeCore {
 
@@ -48,4 +48,4 @@ contract IExchangeCore {
     function cancelOrder(LibOrder.Order memory order)
         public
         returns (bool);
-}
\ No newline at end of file
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ISignatureValidator.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ISignatureValidator.sol
index 806d7c56f..b4a238472 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ISignatureValidator.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ISignatureValidator.sol
@@ -29,4 +29,4 @@ contract ISignatureValidator {
         address signer,
         bytes signature)
         external;
-}
\ No newline at end of file
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
index 078b07816..76e4cf2fe 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
@@ -30,4 +30,4 @@ contract ITransactions {
         bytes data,
         bytes signature)
         external;
-}
\ No newline at end of file
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
index 0ebae309d..d23170b1c 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
@@ -19,8 +19,8 @@
 pragma solidity ^0.4.23;
 pragma experimental ABIEncoderV2;
 
-import "./lib/LibOrder.sol";
-import "./lib/LibFillResults.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibFillResults.sol";
 
 contract IWrapperFunctions is
     LibOrder,
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibExchangeErrors.sol b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibExchangeErrors.sol
new file mode 100644
index 000000000..6ffbdfdca
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibExchangeErrors.sol
@@ -0,0 +1,58 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.23;
+
+contract LibExchangeErrors {
+
+    // Error Codes
+    enum Errors {
+        ORDER_EXPIRED,                     // Order has already expired
+        ORDER_FULLY_FILLED,                // Order has already been fully filled
+        ORDER_CANCELLED,                   // Order has already been cancelled
+        ROUNDING_ERROR_TOO_LARGE,          // Rounding error too large
+        INSUFFICIENT_BALANCE_OR_ALLOWANCE  // Insufficient balance or allowance for token transfer
+    }
+
+    event ExchangeError(uint8 indexed errorId, bytes32 indexed orderHash);
+
+    // Core revert reasons
+    string constant GT_ZERO_AMOUNT_REQUIRED = "Amount must be greater than 0.";
+    string constant SIGNATURE_VALIDATION_FAILED = "Signature validation failed.";
+    string constant INVALID_SENDER = "Invalid `msg.sender`.";
+    string constant INVALID_CONTEXT = "Function called in an invalid context.";
+    string constant INVALID_NEW_MAKER_EPOCH = "Specified salt must be greater than or equal to existing makerEpoch.";
+
+    // Transaction revert reasons
+    string constant DUPLICATE_TRANSACTION_HASH = "Transaction has already been executed.";
+    string constant TRANSACTION_EXECUTION_FAILED = "Transaction execution failed.";
+
+    // Wrapper revert reasons
+    string constant COMPLETE_FILL_FAILED = "Desired fill amount could not be completely filled.";
+    string constant ASSET_DATA_MISMATCH = "Asset data must be the same for each order.";
+
+    // Asset proxy dispatcher revert reasons
+    string constant GT_ZERO_LENGTH_REQUIRED = "Length must be greater than 0.";
+    string constant OLD_ASSET_PROXY_MISMATCH = "Old asset proxy does not match asset proxy at given id.";
+    string constant NEW_ASSET_PROXY_MISMATCH = "New asset proxy id does not match given id.";
+
+    // Signature validator revert reasons
+    string constant INVALID_SIGNATURE_LENGTH = "Invalid signature length.";
+    string constant ILLEGAL_SIGNATURE_TYPE = "Illegal signature type.";
+    string constant UNSUPPORTED_SIGNATURE_TYPE = "Unsupported signature type.";
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibFillResults.sol b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibFillResults.sol
new file mode 100644
index 000000000..3b8f2acf9
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibFillResults.sol
@@ -0,0 +1,47 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.23;
+
+import "../../../utils/SafeMath/SafeMath.sol";
+
+contract LibFillResults is
+    SafeMath
+{
+
+    struct FillResults {
+        uint256 makerAssetFilledAmount;
+        uint256 takerAssetFilledAmount;
+        uint256 makerFeePaid;
+        uint256 takerFeePaid;
+    }
+
+    /// @dev Adds properties of both FillResults instances.
+    ///      Modifies the first FillResults instance specified.
+    /// @param totalFillResults Fill results instance that will be added onto.
+    /// @param singleFillResults Fill results instance that will be added to totalFillResults.
+    function addFillResults(FillResults memory totalFillResults, FillResults memory singleFillResults)
+        internal
+        pure
+    {
+        totalFillResults.makerAssetFilledAmount = safeAdd(totalFillResults.makerAssetFilledAmount, singleFillResults.makerAssetFilledAmount);
+        totalFillResults.takerAssetFilledAmount = safeAdd(totalFillResults.takerAssetFilledAmount, singleFillResults.takerAssetFilledAmount);
+        totalFillResults.makerFeePaid = safeAdd(totalFillResults.makerFeePaid, singleFillResults.makerFeePaid);
+        totalFillResults.takerFeePaid = safeAdd(totalFillResults.takerFeePaid, singleFillResults.takerFeePaid);
+    }
+}
\ No newline at end of file
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibMath.sol b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibMath.sol
new file mode 100644
index 000000000..b48602d19
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibMath.sol
@@ -0,0 +1,72 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.23;
+
+import "../../../utils/SafeMath/SafeMath.sol";
+
+contract LibMath is
+    SafeMath
+{
+
+    /// @dev Calculates partial value given a numerator and denominator.
+    /// @param numerator Numerator.
+    /// @param denominator Denominator.
+    /// @param target Value to calculate partial of.
+    /// @return Partial value of target.
+    function getPartialAmount(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target)
+        internal
+        pure
+        returns (uint256 partialAmount)
+    {
+        partialAmount = safeDiv(
+            safeMul(numerator, target),
+            denominator
+        );
+        return partialAmount;
+    }
+
+    /// @dev Checks if rounding error > 0.1%.
+    /// @param numerator Numerator.
+    /// @param denominator Denominator.
+    /// @param target Value to multiply with numerator/denominator.
+    /// @return Rounding error is present.
+    function isRoundingError(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target)
+        internal
+        pure
+        returns (bool isError)
+    {
+        uint256 remainder = mulmod(target, numerator, denominator);
+        if (remainder == 0) {
+            return false; // No rounding error.
+        }
+
+        uint256 errPercentageTimes1000000 = safeDiv(
+            safeMul(remainder, 1000000),
+            safeMul(numerator, target)
+        );
+        isError = errPercentageTimes1000000 > 1000;
+        return isError;
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibOrder.sol b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibOrder.sol
new file mode 100644
index 000000000..0fe8c8c96
--- /dev/null
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibOrder.sol
@@ -0,0 +1,84 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.23;
+
+contract LibOrder {
+
+    bytes32 constant ORDER_SCHEMA_HASH = keccak256(
+        "address exchangeAddress",
+        "address makerAddress",
+        "address takerAddress",
+        "address feeRecipientAddress",
+        "address senderAddress",
+        "uint256 makerAssetAmount",
+        "uint256 takerAssetAmount",
+        "uint256 makerFee",
+        "uint256 takerFee",
+        "uint256 expirationTimeSeconds",
+        "uint256 salt",
+        "bytes makerAssetData",
+        "bytes takerAssetData"
+    );
+
+    struct Order {
+        address makerAddress;
+        address takerAddress;
+        address feeRecipientAddress;
+        address senderAddress;
+        uint256 makerAssetAmount;
+        uint256 takerAssetAmount;
+        uint256 makerFee;
+        uint256 takerFee;
+        uint256 expirationTimeSeconds;
+        uint256 salt;
+        bytes makerAssetData;
+        bytes takerAssetData;
+    }
+
+    /// @dev Calculates Keccak-256 hash of the order.
+    /// @param order The order structure.
+    /// @return Keccak-256 EIP712 hash of the order.
+    function getOrderHash(Order memory order)
+        internal
+        view
+        returns (bytes32 orderHash)
+    {
+        // TODO: EIP712 is not finalized yet
+        // Source: https://github.com/ethereum/EIPs/pull/712
+        orderHash = keccak256(
+            ORDER_SCHEMA_HASH,
+            keccak256(
+                address(this),
+                order.makerAddress,
+                order.takerAddress,
+                order.feeRecipientAddress,
+                order.senderAddress,
+                order.makerAssetAmount,
+                order.takerAssetAmount,
+                order.makerFee,
+                order.takerFee,
+                order.expirationTimeSeconds,
+                order.salt,
+                order.makerAssetData,
+                order.takerAssetData
+            )
+        );
+        return orderHash;
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol
index b80af9dc1..5b78e70da 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol
@@ -18,8 +18,8 @@
 
 pragma solidity ^0.4.23;
 
-import "../lib/LibOrder.sol";
-import "../lib/LibFillResults.sol";
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
 import "../interfaces/IExchangeCore.sol";
 
 contract MExchangeCore is
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol
index 3075aae15..5e2edbf99 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol
+++ b/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSettlement.sol
@@ -18,7 +18,7 @@
 
 pragma solidity ^0.4.23;
 
-import "../lib/LibOrder.sol";
+import "../libs/LibOrder.sol";
 
 contract MSettlement {
 
diff --git a/packages/contracts/src/contracts/current/test/TestLibs/TestLibs.sol b/packages/contracts/src/contracts/current/test/TestLibs/TestLibs.sol
index 3d199681b..0dc7785b2 100644
--- a/packages/contracts/src/contracts/current/test/TestLibs/TestLibs.sol
+++ b/packages/contracts/src/contracts/current/test/TestLibs/TestLibs.sol
@@ -19,9 +19,9 @@
 pragma solidity ^0.4.23;
 pragma experimental ABIEncoderV2;
 
-import "../../protocol/Exchange/lib/LibMath.sol";
-import "../../protocol/Exchange/lib/LibOrder.sol";
-import "../../protocol/Exchange/lib/LibFillResults.sol";
+import "../../protocol/Exchange/libs/LibMath.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../../protocol/Exchange/libs/LibFillResults.sol";
 
 contract TestLibs is 
     LibMath,
diff --git a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol b/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
index 27e7fa355..6497d3c7a 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
+++ b/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
@@ -23,17 +23,26 @@ import "./IERC20Token.sol";
 
 contract ERC20Token is IERC20Token {
 
+    string constant INSUFFICIENT_BALANCE = "Insufficient balance to complete transfer.";
+    string constant INSUFFICIENT_ALLOWANCE = "Insufficient allowance to complete transfer.";
+    string constant OVERFLOW = "Transfer would result in an overflow.";
+
+    mapping (address => uint256) balances;
+    mapping (address => mapping (address => uint256)) allowed;
+
+    uint256 public totalSupply;
+
     function transfer(address _to, uint256 _value)
         public
         returns (bool)
     {
         require(
             balances[msg.sender] >= _value,
-            "Insufficient balance to complete transfer."
+            INSUFFICIENT_BALANCE
         );
         require(
             balances[_to] + _value >= balances[_to],
-            "Transfer would result in an overflow."
+            OVERFLOW
         );
         balances[msg.sender] -= _value;
         balances[_to] += _value;
@@ -47,15 +56,15 @@ contract ERC20Token is IERC20Token {
     {
         require(
             balances[_from] >= _value,
-            "Insufficient balance to complete transfer."
+            INSUFFICIENT_BALANCE
         );
         require(
             allowed[_from][msg.sender] >= _value,
-            "Insufficient allowance to complete transfer."
+            INSUFFICIENT_ALLOWANCE
         );
         require(
             balances[_to] + _value >= balances[_to],
-            "Transfer would result in an overflow."
+            OVERFLOW
         );
         balances[_to] += _value;
         balances[_from] -= _value;
@@ -87,8 +96,5 @@ contract ERC20Token is IERC20Token {
     {
         return allowed[_owner][_spender];
     }
-
-    mapping (address => uint256) balances;
-    mapping (address => mapping (address => uint256)) allowed;
-    uint256 public totalSupply;
 }
+
diff --git a/packages/contracts/src/contracts/current/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol b/packages/contracts/src/contracts/current/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
index 4aedced49..395e5d356 100644
--- a/packages/contracts/src/contracts/current/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
+++ b/packages/contracts/src/contracts/current/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
@@ -37,15 +37,15 @@ contract UnlimitedAllowanceToken is ERC20Token {
         uint256 allowance = allowed[_from][msg.sender];
         require(
             balances[_from] >= _value,
-            "Insufficient balance to complete transfer."
+            INSUFFICIENT_BALANCE
         );
         require(
             allowance >= _value,
-            "Insufficient allowance to complete transfer."
+            INSUFFICIENT_ALLOWANCE
         );
         require(
             balances[_to] + _value >= balances[_to],
-            "Transfer would result in an overflow."
+            OVERFLOW
         );
         balances[_to] += _value;
         balances[_from] -= _value;
diff --git a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol b/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
index 3eba0708f..3c5531e35 100644
--- a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
+++ b/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
@@ -20,6 +20,10 @@ pragma solidity ^0.4.23;
 
 contract LibBytes {
 
+    // Revert reasons
+    string constant GTE_20_LENGTH_REQUIRED = "Length must be greater than or equal to 20.";
+    string constant GTE_32_LENGTH_REQUIRED = "Length must be greater than or equal to 32.";
+
     /// @dev Tests equality of two byte arrays.
     /// @param lhs First byte array to compare.
     /// @param rhs Second byte array to compare.
@@ -65,7 +69,7 @@ contract LibBytes {
     {
         require(
             b.length >= index + 20,  // 20 is length of address
-            "Cannot read address from byte array shorter than 20 bytes."
+            GTE_20_LENGTH_REQUIRED
         ); 
 
         // Add offset to index:
@@ -96,7 +100,7 @@ contract LibBytes {
     {
         require(
             b.length >= index + 20,  // 20 is length of address
-            "Cannot write address to byte array shorter than 20 bytes."
+            GTE_20_LENGTH_REQUIRED
         ); 
 
         // Add offset to index:
@@ -134,7 +138,7 @@ contract LibBytes {
     {
         require(
             b.length >= index + 32,
-            "Cannot read 32 bytes from byte array shorter than 32 bytes."
+            GTE_32_LENGTH_REQUIRED
         );
 
         // Arrays are prefixed by a 256 bit length parameter
@@ -160,7 +164,7 @@ contract LibBytes {
     {
         require(
             b.length >= index + 32,
-            "Cannot write 32 bytes to byte array shorter than 32 bytes."
+            GTE_32_LENGTH_REQUIRED
         );
 
         // Arrays are prefixed by a 256 bit length parameter