Fix fallback Unpacker.read() (#388)

Fixes #352.

Author: methane

msgpack/fallback.py

@@ -357,7 +357,9 @@ def _get_extradata(self):
         return self._buffer[self._buff_i :]
 
     def read_bytes(self, n):
-        return self._read(n)
+        ret = self._read(n)
+        self._consume()
+        return ret
 
     def _read(self, n):
         # (int) -> bytearray

test/test_sequnpack.py

@@ -93,6 +93,15 @@ def test_readbytes():
     assert unpacker.unpack() == ord(b"a")
     assert unpacker.unpack() == ord(b"r")
 
+    # Issue 352
+    u = Unpacker()
+    u.feed(b"x")
+    assert bytes(u.read_bytes(1)) == b"x"
+    with raises(StopIteration):
+        next(u)
+    u.feed(b"\1")
+    assert next(u) == 1
+
 
 def test_issue124():
     unpacker = Unpacker()