Include threshold balance in constructor of BalanceThresholdFilter contract

packages/contracts/contracts/extensions/BalanceThresholdFilter/BalanceThresholdFilter.sol

@@ -26,10 +26,19 @@ import "./MixinBalanceThresholdFilterCore.sol";
 
 contract BalanceThresholdFilter is MixinBalanceThresholdFilterCore {
 
-    constructor(address exchange, address thresholdAsset)
+    /// @dev Constructs BalanceThresholdFilter.
+    /// @param exchange Address of 0x exchange.
+    /// @param thresholdAsset The asset that must be held by makers/takers.
+    /// @param thresholdBalance The minimum balance of `thresholdAsset` that must be held by makers/takers.
+    constructor(
+        address exchange,
+        address thresholdAsset,
+        uint256 thresholdBalance
+    )
         public
     {
         EXCHANGE = IExchange(exchange);
         THRESHOLD_ASSET = IThresholdAsset(thresholdAsset);
+        THRESHOLD_BALANCE = thresholdBalance;
     }
 }

packages/contracts/contracts/extensions/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol

@@ -263,6 +263,7 @@ contract MixinBalanceThresholdFilterCore is MBalanceThresholdFilterCore {
 
             // Validate addresses
             let thresholdAssetAddress := sload(THRESHOLD_ASSET_slot)
+            let thresholdBalance := sload(THRESHOLD_BALANCE_slot)
             for {let addressToValidate := addressesToValidateElementPtr} lt(addressToValidate, addressesToValidateElementEndPtr) {addressToValidate := add(addressToValidate, 0x20)} {
                 // Construct calldata for `THRESHOLD_ASSET.balanceOf`
                 mstore(freeMemPtr, 0x70a0823100000000000000000000000000000000000000000000000000000000)
@@ -294,7 +295,7 @@ contract MixinBalanceThresholdFilterCore is MBalanceThresholdFilterCore {
 
                 // Revert if balance not held
                 let addressBalance := mload(freeMemPtr)
-                if eq(addressBalance, 0) {
+                if lt(addressBalance, thresholdBalance) {
                     // Revert with `Error("AT_LEAST_ONE_ADDRESS_DOES_NOT_MEET_BALANCE_THRESHOLD")`
                     mstore(0x00, 0x08c379a000000000000000000000000000000000000000000000000000000000)
                     mstore(0x20, 0x0000002000000000000000000000000000000000000000000000000000000000)

packages/contracts/contracts/extensions/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol

@@ -25,9 +25,16 @@ import "../interfaces/IThresholdAsset.sol";
 
 contract MBalanceThresholdFilterCore {
 
+    // Points to 0x exchange contract
     IExchange internal EXCHANGE;
+
+    // The asset that must be held by makers/takers
     IThresholdAsset internal THRESHOLD_ASSET;
 
+    // The minimum balance of `THRESHOLD_ASSET` that must be held by makers/takers
+    uint256 internal THRESHOLD_BALANCE;
+
+    // Addresses that hold at least `THRESHOLD_BALANCE` of `THRESHOLD_ASSET`
     event ValidatedAddresses (
         address[] addresses
     );

packages/contracts/test/extensions/balance_threshold_filter.ts

@@ -126,12 +126,14 @@ describe.only(ContractName.BalanceThresholdFilter, () => {
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(compliantMakerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
         // Deploy Compliant Forwarder
+        const erc721BalanceThreshold = new BigNumber(1);
         compliantForwarderInstance = await BalanceThresholdFilterContract.deployFrom0xArtifactAsync(
             artifacts.BalanceThresholdFilter,
             provider,
             txDefaults,
             exchangeInstance.address,
             yesTokenInstance.address,
+            erc721BalanceThreshold
         );
         /*
         const compliantForwarderContract = new BalanceThresholdFilterContract(