Fix tests

contracts/staking/contracts/src/fees/MixinExchangeFees.sol

@@ -126,9 +126,10 @@ contract MixinExchangeFees is
         activePoolsThisEpoch[poolId] = pool;
     }
 
-    /// @dev Returns the total balance of this contract, including WETH.
+    /// @dev Returns the total balance of this contract, including WETH,
+    ///      minus any WETH that has been reserved for rewards.
     /// @return totalBalance Total balance.
-    function getTotalBalance()
+    function getAvailableBalance()
         external
         view
         returns (uint256 totalBalance)

contracts/staking/contracts/test/TestStakingNoWETH.sol

@@ -42,9 +42,14 @@ contract TestStakingNoWETH is
         return true;
     }
 
-    function _wrapEthAndGetWethBalance()
+    function _wrapEth()
         internal
-        returns (uint256 balance)
+    {}
+
+    function _getAvailableWethBalance()
+        internal
+        view
+        returns (uint256)
     {
         return address(this).balance;
     }

contracts/staking/test/actors/finalizer_actor.ts

@@ -241,9 +241,7 @@ export class FinalizerActor extends BaseActor {
                 this._stakingApiWrapper.stakingContract.getActiveStakingPoolThisEpoch.callAsync(poolId),
             ),
         );
-        const totalRewards = await this._stakingApiWrapper.utils.getEthAndWethBalanceOfAsync(
-            this._stakingApiWrapper.stakingContract.address,
-        );
+        const totalRewards = await this._stakingApiWrapper.stakingContract.getAvailableBalance.callAsync();
         const totalFeesCollected = BigNumber.sum(...activePools.map(p => p.feesCollected));
         const totalWeightedStake = BigNumber.sum(...activePools.map(p => p.weightedStake));
         if (totalRewards.eq(0) || totalFeesCollected.eq(0) || totalWeightedStake.eq(0)) {