Merge the governors test suites into one reusable set of tests

contracts/governance/test/BaseTest.t.sol

@@ -47,16 +47,9 @@ contract BaseTest is Test {
 
     function setupGovernance()
         internal
-        returns (
-            IERC20,
-            ZRXWrappedToken,
-            ZeroExVotes,
-            ZeroExTimelock,
-            ZeroExTimelock,
-            ZeroExProtocolGovernor,
-            ZeroExTreasuryGovernor
-        )
+        returns (IERC20, ZRXWrappedToken, ZeroExVotes, ZeroExTimelock, ZeroExTimelock, address, address)
     {
+        vm.startPrank(account1);
         (IERC20 zrxToken, ZRXWrappedToken token, ZeroExVotes votes) = setupZRXWrappedToken();
 
         address[] memory proposers = new address[](0);
@@ -82,8 +75,17 @@ contract BaseTest is Test {
         treasuryTimelock.grantRole(treasuryTimelock.PROPOSER_ROLE(), address(treasuryGovernor));
         treasuryTimelock.grantRole(treasuryTimelock.EXECUTOR_ROLE(), address(treasuryGovernor));
         treasuryTimelock.grantRole(treasuryTimelock.CANCELLER_ROLE(), address(treasuryGovernor));
+        vm.stopPrank();
 
-        return (zrxToken, token, votes, protocolTimelock, treasuryTimelock, protocolGovernor, treasuryGovernor);
+        return (
+            zrxToken,
+            token,
+            votes,
+            protocolTimelock,
+            treasuryTimelock,
+            address(protocolGovernor),
+            address(treasuryGovernor)
+        );
     }
 
     function setupZRXWrappedToken() internal returns (IERC20, ZRXWrappedToken, ZeroExVotes) {

contracts/governance/test/IZeroExGovernor.sol

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2023 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 ^0.8.17;
+
+import "@openzeppelin/governance/IGovernor.sol";
+import "@openzeppelin/governance/extensions/IGovernorTimelock.sol";
+
+abstract contract IZeroExGovernor is IGovernor, IGovernorTimelock {
+    function token() public virtual returns (address);
+
+    function securityCouncil() public virtual returns (address);
+
+    function proposalThreshold() public view virtual returns (uint256);
+
+    function cancel(
+        address[] memory targets,
+        uint256[] memory values,
+        bytes[] memory calldatas,
+        bytes32 descriptionHash
+    ) public virtual;
+
+    function assignSecurityCouncil(address _securityCouncil) public virtual;
+
+    function setVotingDelay(uint256 newVotingDelay) public virtual;
+
+    function setVotingPeriod(uint256 newVotingPeriod) public virtual;
+
+    function setProposalThreshold(uint256 newProposalThreshold) public virtual;
+
+    function proposalVotes(
+        uint256 proposalId
+    ) public view virtual returns (uint256 againstVotes, uint256 forVotes, uint256 abstainVotes);
+}

contracts/governance/test/ZRXWrappedTokenTest.t.sol

@@ -28,8 +28,8 @@ contract ZRXWrappedTokenTest is BaseTest {
     ZeroExVotes private votes;
 
     function setUp() public {
-        vm.startPrank(account1);
         (token, wToken, votes, , , , ) = setupGovernance();
+        vm.startPrank(account1);
         token.transfer(account2, 100e18);
         token.transfer(account3, 200e18);
         vm.stopPrank();