clarifies why a test case is valid under the new implementation

consensus/mempool_test.go

@@ -75,7 +75,7 @@ func TestMempoolProgressInHigherRound(t *testing.T) {
 	timeoutCh := subscribe(cs.eventBus, types.EventQueryTimeoutPropose)
 	cs.setProposal = func(proposal *types.Proposal) error {
 		if cs.Height == 2 && cs.Round == 0 {
-			// dont set the proposal in round 0 so we timeout and
+			// don't set the proposal in round 0 so we timeout and
 			// go to next round
 			cs.Logger.Info("Ignoring set proposal at height 2, round 0")
 			return nil
@@ -91,7 +91,12 @@ func TestMempoolProgressInHigherRound(t *testing.T) {
 	round = 0
 
 	ensureNewRound(newRoundCh, height, round) // first round at next height
-	deliverTxsRange(cs, 0, 1)                 // we deliver txs, but dont set a proposal so we get the next round
+	deliverTxsRange(cs, 0, 1)                 // we deliver txs, but don't set a proposal so we get the next round
+	// The following line checks if we proceed to the next round after cs.config.TimeoutPropose.Nanoseconds().
+	// In the versioned timeout implementation, the timeout propose is version-dependent.
+	// However, in this test case, cs is created with an empty previous state,
+	// so there's no timeout propose in the previous state.
+	// Therefore, we fall back to the timeout propose in the config, making this test case valid.
 	ensureNewTimeout(timeoutCh, height, round, cs.config.TimeoutPropose.Nanoseconds())
 
 	round++                                   // moving to the next round