diff --git a/hbmqtt/utils.py b/hbmqtt/utils.py
index 1a4ab84..7ab2593 100644
--- a/hbmqtt/utils.py
+++ b/hbmqtt/utils.py
@@ -7,7 +7,7 @@ from hbmqtt.streams.errors import NoDataException
 def bytes_to_hex_str(data):
     return '0x' + ''.join(format(b, '02x') for b in data)
 
-def hex_to_int(data):
+def bytes_to_int(data):
     return int.from_bytes(data, byteorder='big')
 
 @asyncio.coroutine
@@ -19,4 +19,7 @@ def read_or_raise(reader, n=-1):
 
 @asyncio.coroutine
 def read_string(reader):
-    length = yield from read_or_raise(reader, 2)
\ No newline at end of file
+    length_bytes = yield from read_or_raise(reader, 2)
+    str_length = bytes_to_int(length_bytes)
+    byte_str = yield from read_or_raise(reader, str_length)
+    return byte_str.decode()
\ No newline at end of file
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..4a38929
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,31 @@
+# Copyright (c) 2015 Nicolas JOUANIN
+#
+# See the file license.txt for copying permission.
+import unittest
+import asyncio
+from hbmqtt.utils import (
+    bytes_to_hex_str,
+    bytes_to_int,
+    read_string,
+)
+from hbmqtt.message import MessageType
+
+class TestUtils(unittest.TestCase):
+    def setUp(self):
+        self.loop = asyncio.new_event_loop()
+
+    def test_bytes_to_hex_str(self):
+        ret = bytes_to_hex_str(b'\x7f')
+        self.assertEqual(ret, '0x7f')
+
+    def test_bytes_to_int(self):
+        ret = bytes_to_int(b'\x7f')
+        self.assertEqual(ret, 127)
+        ret = bytes_to_int(b'\xff\xff')
+        self.assertEqual(ret, 65535)
+
+    def test_read_string(self):
+        stream = asyncio.StreamReader(loop=self.loop)
+        stream.feed_data(b'\x00\x02AA')
+        ret = self.loop.run_until_complete(read_string(stream))
+        self.assertEqual(ret, 'AA')
\ No newline at end of file