diff --git a/consensus/replay_test.go b/consensus/replay_test.go
index a1e06c65c..7a06d96f1 100644
--- a/consensus/replay_test.go
+++ b/consensus/replay_test.go
@@ -44,13 +44,6 @@ func init() {
 // the `Handshake Tests` are for failures in applying the block.
 // With the help of the WAL, we can recover from it all!
 
-// NOTE: Files in this dir are generated by running the `build.sh` therein.
-// It's a simple way to generate wals for a single block, or multiple blocks, with random transactions,
-// and different part sizes. The output is not deterministic.
-// It should only have to be re-run if there is some breaking change to the consensus data structures (eg. blocks, votes)
-// or to the behaviour of the app (eg. computes app hash differently)
-var data_dir = path.Join(cmn.GoPath(), "src/github.com/tendermint/tendermint/consensus", "test_data")
-
 //------------------------------------------------------------------------------------------
 // WAL Tests
 
@@ -496,10 +489,13 @@ func makeBlockchainFromWAL(wal WAL) ([]*types.Block, []*types.Commit, error) {
 
 	// log.Notice("Build a blockchain by reading from the WAL")
 
-	var blockParts *types.PartSet
 	var blocks []*types.Block
 	var commits []*types.Commit
 
+	var thisBlockParts *types.PartSet
+	var thisBlockCommit *types.Commit
+	var height int64
+
 	dec := NewWALDecoder(gr)
 	for {
 		msg, err := dec.Decode()
@@ -515,42 +511,60 @@ func makeBlockchainFromWAL(wal WAL) ([]*types.Block, []*types.Commit, error) {
 		}
 
 		switch p := piece.(type) {
-		case *types.PartSetHeader:
+		case EndHeightMessage:
 			// if its not the first one, we have a full block
-			if blockParts != nil {
+			if thisBlockParts != nil {
 				var n int
-				block := wire.ReadBinary(&types.Block{}, blockParts.GetReader(), 0, &n, &err).(*types.Block)
+				block := wire.ReadBinary(&types.Block{}, thisBlockParts.GetReader(), 0, &n, &err).(*types.Block)
+				if err != nil {
+					panic(err)
+				}
+				if block.Height != height+1 {
+					panic(cmn.Fmt("read bad block from wal. got height %d, expected %d", block.Height, height+1))
+				}
+				commitHeight := thisBlockCommit.Precommits[0].Height
+				if commitHeight != height+1 {
+					panic(cmn.Fmt("commit doesnt match. got height %d, expected %d", commitHeight, height+1))
+				}
 				blocks = append(blocks, block)
+				commits = append(commits, thisBlockCommit)
+				height += 1
 			}
-			blockParts = types.NewPartSetFromHeader(*p)
+		case *types.PartSetHeader:
+			thisBlockParts = types.NewPartSetFromHeader(*p)
 		case *types.Part:
-			_, err := blockParts.AddPart(p, false)
+			_, err := thisBlockParts.AddPart(p, false)
 			if err != nil {
 				return nil, nil, err
 			}
 		case *types.Vote:
 			if p.Type == types.VoteTypePrecommit {
-				commit := &types.Commit{
+				thisBlockCommit = &types.Commit{
 					BlockID:    p.BlockID,
 					Precommits: []*types.Vote{p},
 				}
-				commits = append(commits, commit)
 			}
 		}
 	}
 	// grab the last block too
 	var n int
-	block := wire.ReadBinary(&types.Block{}, blockParts.GetReader(), 0, &n, &err).(*types.Block)
+	block := wire.ReadBinary(&types.Block{}, thisBlockParts.GetReader(), 0, &n, &err).(*types.Block)
+	if err != nil {
+		panic(err)
+	}
+	if block.Height != height+1 {
+		panic(cmn.Fmt("read bad block from wal. got height %d, expected %d", block.Height, height+1))
+	}
+	commitHeight := thisBlockCommit.Precommits[0].Height
+	if commitHeight != height+1 {
+		panic(cmn.Fmt("commit doesnt match. got height %d, expected %d", commitHeight, height+1))
+	}
 	blocks = append(blocks, block)
+	commits = append(commits, thisBlockCommit)
 	return blocks, commits, nil
 }
 
 func readPieceFromWAL(msg *TimedWALMessage) interface{} {
-	// skip meta messages
-	if _, ok := msg.Msg.(EndHeightMessage); ok {
-		return nil
-	}
-
 	// for logging
 	switch m := msg.Msg.(type) {
 	case msgInfo:
@@ -562,6 +576,8 @@ func readPieceFromWAL(msg *TimedWALMessage) interface{} {
 		case *VoteMessage:
 			return msg.Vote
 		}
+	case EndHeightMessage:
+		return m
 	}
 
 	return nil
diff --git a/consensus/wal_generator.go b/consensus/wal_generator.go
index c43e7c635..157d6d40e 100644
--- a/consensus/wal_generator.go
+++ b/consensus/wal_generator.go
@@ -77,7 +77,7 @@ func WALWithNBlocks(numBlocks int) (data []byte, err error) {
 	var b bytes.Buffer
 	wr := bufio.NewWriter(&b)
 	numBlocksWritten := make(chan struct{})
-	wal := &byteBufferWAL{enc: NewWALEncoder(wr), heightToStop: int64(numBlocks), signalWhenStopsTo: numBlocksWritten}
+	wal := newByteBufferWAL(NewWALEncoder(wr), int64(numBlocks), numBlocksWritten)
 	// see wal.go#103
 	wal.Save(EndHeightMessage{0})
 	consensusState.wal = wal
@@ -147,6 +147,14 @@ type byteBufferWAL struct {
 // needed for determinism
 var fixedTime, _ = time.Parse(time.RFC3339, "2017-01-02T15:04:05Z")
 
+func newByteBufferWAL(enc *WALEncoder, nBlocks int64, signalStop chan struct{}) *byteBufferWAL {
+	return &byteBufferWAL{
+		enc:               enc,
+		heightToStop:      nBlocks,
+		signalWhenStopsTo: signalStop,
+	}
+}
+
 // Save writes message to the internal buffer except when heightToStop is
 // reached, in which case it will signal the caller via signalWhenStopsTo and
 // skip writing.