Fix codecov: fix app hash in state rollback (backport #7837) (#7881)

state/rollback.go

@@ -41,13 +41,13 @@ func Rollback(bs BlockStore, ss Store) (int64, []byte, error) {
 	rollbackHeight := invalidState.LastBlockHeight - 1
 	rollbackBlock := bs.LoadBlockMeta(rollbackHeight)
 	if rollbackBlock == nil {
-		return -1, nil, fmt.Errorf("block at height %d not found", rollbackHeight)
+		return -1, nil, fmt.Errorf("block at RollbackHeight %d not found", rollbackHeight)
 	}
 	// We also need to retrieve the latest block because the app hash and last
 	// results hash is only agreed upon in the following block.
 	latestBlock := bs.LoadBlockMeta(invalidState.LastBlockHeight)
 	if latestBlock == nil {
-		return -1, nil, fmt.Errorf("block at height %d not found", invalidState.LastBlockHeight)
+		return -1, nil, fmt.Errorf("block at LastBlockHeight %d not found", invalidState.LastBlockHeight)
 	}
 
 	_, prevVoterSet, _, _, err := ss.LoadVoters(rollbackHeight, nil)

state/rollback_test.go

@@ -102,12 +102,18 @@ func TestRollbackNoBlocks(t *testing.T) {
 	stateStore := setupStateStore(t, height)
 	blockStore := &mocks.BlockStore{}
 	blockStore.On("Height").Return(height)
-	blockStore.On("LoadBlockMeta", height).Return(nil)
-	blockStore.On("LoadBlockMeta", height-1).Return(nil)
+	blockStore.On("LoadBlockMeta", height-1).Once().Return(nil)
 
 	_, _, err := state.Rollback(blockStore, stateStore)
 	require.Error(t, err)
-	require.Contains(t, err.Error(), "block at height 99 not found")
+	require.Contains(t, err.Error(), "block at RollbackHeight 99 not found")
+
+	blockStore.On("LoadBlockMeta", height-1).Once().Return(&types.BlockMeta{})
+	blockStore.On("LoadBlockMeta", height).Return(nil)
+
+	_, _, err = state.Rollback(blockStore, stateStore)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "block at LastBlockHeight 100 not found")
 }
 
 func TestRollbackDifferentStateHeight(t *testing.T) {