Simulate the passage of time

test/FlexVotingClient.invariants.t.sol

@@ -40,26 +40,27 @@ contract FlexVotingInvariantSetup is Test {
     // Proposal will underflow if we're on the zero block.
     if (block.number == 0) vm.roll(1);
 
-    bytes4[] memory selectors = new bytes4[](5);
+    bytes4[] memory selectors = new bytes4[](6);
     selectors[0] = FlexVotingClientHandler.deposit.selector;
     selectors[1] = FlexVotingClientHandler.propose.selector;
     selectors[2] = FlexVotingClientHandler.expressVote.selector;
     selectors[3] = FlexVotingClientHandler.castVote.selector;
     selectors[4] = FlexVotingClientHandler.withdraw.selector;
+    selectors[5] = FlexVotingClientHandler.roll.selector;
 
     targetSelector(FuzzSelector({addr: address(handler), selectors: selectors}));
     targetContract(address(handler));
   }
 }
 
 contract FlexVotingInvariantTest is FlexVotingInvariantSetup {
-  // // We want to make sure that things like this cannot happen:
-  // // - user A deposits X
-  // // - user A expresses FOR on proposal P
-  // // - castVote is called for P, user A's votes are cast
-  // // - stuff we can't imagine happens...
-  // // - user A expresses again on proposal P
-  // // - castVote is called for P, user A gets more votes through
+  // We want to make sure that things like this cannot happen:
+  // - user A deposits X
+  // - user A expresses FOR on proposal P
+  // - castVote is called for P, user A's votes are cast
+  // - stuff we can't imagine happens...
+  // - user A expresses again on proposal P
+  // - castVote is called for P, user A gets more votes through
   function invariant_OneVotePerActorPerProposal() public view {
     handler.callSummary();
 

test/handlers/FlexVotingClientHandler.sol

@@ -179,6 +179,13 @@ contract FlexVotingClientHandler is Test {
     return actors.length();
   }
 
+  // Simulate the passage of time, which materially changes governance behavior.
+  function roll(uint256 _seed) external countCall("roll") {
+    vm.assume(proposals.length() > 0);
+    uint256 _blocks = _bound(_seed, 1, governor.votingPeriod() / 10);
+    vm.roll(block.number + _blocks);
+  }
+
   // TODO This always creates a new actor. Should it?
   function deposit(uint208 _amount)
     external
@@ -341,6 +348,7 @@ contract FlexVotingClientHandler is Test {
     console2.log("expressVote:", calls["expressVote"].count);
     console2.log("castVote:", calls["castVote"].count);
     console2.log("propose:", calls["propose"].count);
+    console2.log("roll:", calls["roll"].count);
     console2.log("-------------------");
     console2.log("actor count:", actors.length());
     console2.log("voter count:", voters.length());