diff --git a/src/tscut/tests/h264/test_bitstream.py b/src/tscut/tests/h264/test_bitstream.py
new file mode 100644
index 0000000..c9ac24f
--- /dev/null
+++ b/src/tscut/tests/h264/test_bitstream.py
@@ -0,0 +1,37 @@
+from tscut.h264.bitstream import (
+    read_bit,
+    read_byte,
+    read_word
+)
+
+def test_read_bit_1():
+    buf = bytes(10)
+    for p in range(80):
+        pos, b = read_bit(buf, p)
+        assert pos == p+1 and b == 0
+
+def test_read_bit_2():
+    buf = b'\xFF'*10
+    for p in range(80):
+        pos, b = read_bit(buf, p)
+        assert pos == p+1 and b == 1
+
+def test_read_byte_1():
+    buf = bytes(10)
+    for p in range(10):
+        pos, b = read_byte(buf, p*8)
+        assert pos == (p+1)*8 and b == 0
+
+def test_read_byte_2():
+    buf = bytes(10)
+    buf = b'\xFF'*10
+    for p in range(10):
+        pos, b = read_byte(buf, p*8)
+        assert pos == (p+1)*8 and b == 0xFF
+
+def test_read_word_1():
+    buf = bytes(20)
+    for p in range(10):
+        pos, b = read_word(buf, p*16)
+        assert pos == (p+1)*16 and b == 0
+