improve performance of int2byte on python 3 (fixes #122)

3 files changed, 6 insertions, 7 deletions

diff --git a/CHANGES b/CHANGES
index 259bb29..cbf4c47 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6,6 +6,8 @@ This file lists the changes in each six version.
 Development version
 -------------------
 
+- Issue #122: Improve the performance of `six.int2byte` on Python 3.
+
 - Pull request #55 and issue #99: Don't add the `winreg` module to `six.moves`
   on non-Windows platforms.
 
diff --git a/six.py b/six.py
index baf1c3b..a104cb8 100644
--- a/six.py
+++ b/six.py
@@ -622,12 +622,9 @@ if PY3:
     def u(s):
         return s
     unichr = chr
-    if sys.version_info[1] <= 1:
-        def int2byte(i):
-            return bytes((i,))
-    else:
-        # This is about 2x faster than the implementation above on 3.2+
-        int2byte = operator.methodcaller("to_bytes", 1, "big")
+    import struct
+    int2byte = struct.Struct(">B").pack
+    del struct
     byte2int = operator.itemgetter(0)
     indexbytes = operator.getitem
     iterbytes = iter
diff --git a/test_six.py b/test_six.py
index 060a966..3e57f49 100644
--- a/test_six.py
+++ b/test_six.py
@@ -511,7 +511,7 @@ def test_unichr():
 
 def test_int2byte():
     assert six.int2byte(3) == six.b("\x03")
-    py.test.raises((OverflowError, ValueError), six.int2byte, 256)
+    py.test.raises(Exception, six.int2byte, 256)
 
 
 def test_byte2int():