diff --git a/passes/bytes.cc b/passes/bytes.cc
index 93fe028..43ff1cb 100644
--- a/passes/bytes.cc
+++ b/passes/bytes.cc
@@ -7,14 +7,14 @@ extern "C" {
 
 void ByteSwap(uint8_t *__restrict__ dst, const uint8_t *__restrict__ src,
               size_t len) {
-  static const size_t n = sizeof(uint64_t);
-  uint64_t *__restrict__ u64_dst = reinterpret_cast<uint64_t *>(dst);
-  const uint64_t *__restrict__ u64_src =
-      reinterpret_cast<const uint64_t *>(src);
+  static constexpr size_t n = sizeof(uint64_t);
+  auto dst64 = reinterpret_cast<uint64_t *>(dst);
+  auto src64 = reinterpret_cast<const uint64_t *>(src);
   const size_t m = len / n;
+  const size_t r = m * n;
   for (size_t i = 0; i < m; ++i)
-    u64_dst[i] = __builtin_bswap64(u64_src[m - 1 - i]);
-  for (size_t i = m * n; i < len; ++i)
-    dst[i] = src[i];
+    dst64[i] = __builtin_bswap64(src64[m - 1 - i]);
+  for (size_t i = 0; i < len - r; ++i)
+    dst[r + i] = src[len - 1 - i];
 }
 }
diff --git a/passes/passes_test.go b/passes/passes_test.go
index 8720d47..fa7743b 100644
--- a/passes/passes_test.go
+++ b/passes/passes_test.go
@@ -22,8 +22,9 @@ func TestCompress(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&RandCompressor{})
 	pm.AddPass(&RandDecompressor{})
-	r, err := pm.RunOnBytes([]byte("wtf"))
-	if string(r) != "wtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -34,8 +35,9 @@ func TestLZ4Compress(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&LZ4Compressor{})
 	pm.AddPass(&LZ4Decompressor{})
-	r, err := pm.RunOnBytes([]byte("wtfwtfwtfwtf"))
-	if string(r) != "wtfwtfwtfwtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -46,8 +48,9 @@ func TestSnappyCompress(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&SnappyEncoder{})
 	pm.AddPass(&SnappyDecoder{})
-	r, err := pm.RunOnBytes([]byte("wtfwtfwtfwtf"))
-	if string(r) != "wtfwtfwtfwtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -58,8 +61,9 @@ func TestRandCompress(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&RandCompressor{})
 	pm.AddPass(&RandDecompressor{})
-	r, err := pm.RunOnBytes([]byte("wtfwtfwtfwtf"))
-	if string(r) != "wtfwtfwtfwtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -106,8 +110,9 @@ func TestRC4(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&RC4Enc{})
 	pm.AddPass(&RC4Dec{})
-	r, err := pm.RunOnBytes([]byte("wtf"))
-	if string(r) != "wtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -118,8 +123,9 @@ func TestOBFS(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&OBFSEncoder{})
 	pm.AddPass(&OBFSDecoder{})
-	r, err := pm.RunOnBytes([]byte("wtf"))
-	if string(r) != "wtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -130,20 +136,34 @@ func TestRotateLeft(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&RotateLeft{})
 	pm.AddPass(&DeRotateLeft{})
-	r, err := pm.RunOnBytes([]byte("wtf"))
-	if string(r) != "wtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
 	}
 }
 
-func TestByteSwap(t *testing.T) {
+func TestByteSwapTwice(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&ByteSwap{})
 	pm.AddPass(&ByteSwap{})
-	r, err := pm.RunOnBytes([]byte("wtfwtfwtfwtfwtfwtfwtf"))
-	if string(r) != "wtfwtfwtfwtfwtfwtfwtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
+		t.Log(err)
+		t.Log(r)
+		t.Fail()
+	}
+}
+
+func TestByteSwap(t *testing.T) {
+	pm := core.NewLegacyPassManager()
+	pm.AddPass(&ByteSwap{})
+	const s = "0123456789ABCDE"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != "76543210EDCBA98" || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()
@@ -154,8 +174,9 @@ func TestIntegration(t *testing.T) {
 	pm := core.NewLegacyPassManager()
 	pm.AddPass(&ByteSwap{}).AddPass(&OBFSEncoder{}).AddPass(&LZ4Compressor{}).AddPass(&Reverse{}).AddPass(&RotateLeft{})
 	pm.AddPass(&DeRotateLeft{}).AddPass(&Reverse{}).AddPass(&LZ4Decompressor{}).AddPass(&OBFSDecoder{}).AddPass(&ByteSwap{})
-	r, err := pm.RunOnBytes([]byte("wtfwtfwtf"))
-	if string(r) != "wtfwtfwtf" || err != nil {
+	const s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	r, err := pm.RunOnBytes([]byte(s))
+	if string(r) != s || err != nil {
 		t.Log(err)
 		t.Log(r)
 		t.Fail()