python: Add test for python3 and fix found problems.

test3/test_pack.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+# coding: utf-8
+
+from nose import main
+from nose.tools import *
+
+from msgpack import packs, unpacks
+
+def check(data):
+    re = unpacks(packs(data))
+    assert_equal(re, data)
+
+def testPack():
+    test_data = [
+            0, 1, 127, 128, 255, 256, 65535, 65536,
+            -1, -32, -33, -128, -129, -32768, -32769,
+            1.0,
+        b"", b"a", b"a"*31, b"a"*32,
+        None, True, False,
+        (), ((),), ((), None,), 
+        {None: 0}, 
+        (1<<23), 
+        ]
+    for td in test_data:
+        check(td)
+
+if __name__ == '__main__':
+    main()