Add tests for cmp_to_key.

Adopt PEP 8 compliant function name.
Factor-out existing uses cmp_to_key.
Update documentation to use internal pointers instead of external resource.

4 files changed, 10 insertions, 24 deletions

diff --git a/Lib/functools.py b/Lib/functools.py
index d31b090..ad1cccc 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -76,7 +76,7 @@ def total_ordering(cls):
             setattr(cls, opname, opfunc)
     return cls
 
-def CmpToKey(mycmp):
+def cmp_to_key(mycmp):
     'Convert a cmp= function into a key= function'
     class K(object):
         def __init__(self, obj, *args):
diff --git a/Lib/pstats.py b/Lib/pstats.py
index 0effa1c..8b60810 100644
--- a/Lib/pstats.py
+++ b/Lib/pstats.py
@@ -37,6 +37,7 @@ import os
 import time
 import marshal
 import re
+from functools import cmp_to_key
 
 __all__ = ["Stats"]
 
@@ -238,7 +239,7 @@ class Stats:
             stats_list.append((cc, nc, tt, ct) + func +
                               (func_std_string(func), func))
 
-        stats_list.sort(key=CmpToKey(TupleComp(sort_tuple).compare))
+        stats_list.sort(key=cmp_to_key(TupleComp(sort_tuple).compare))
 
         self.fcn_list = fcn_list = []
         for tuple in stats_list:
@@ -471,16 +472,6 @@ class TupleComp:
                 return direction
         return 0
 
-def CmpToKey(mycmp):
-    """Convert a cmp= function into a key= function"""
-    class K(object):
-        def __init__(self, obj):
-            self.obj = obj
-        def __lt__(self, other):
-            return mycmp(self.obj, other.obj) == -1
-    return K
-
-
 #**************************************************************************
 # func_name is a triple (file:string, line:int, name:string)
 
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index 2549e05..44992b8 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -338,7 +338,12 @@ class TestReduce(unittest.TestCase):
         self.assertEqual(reduce(42, "", "1"), "1") # func is never called with one item
         self.assertRaises(TypeError, reduce, 42, (42, 42))
 
-
+class TestCmpToKey(unittest.TestCase):
+    def test_cmp_to_key(self):
+        def mycmp(x, y):
+            return y - x
+        self.assertEqual(sorted(range(5), key=functools.cmp_to_key(mycmp)),
+                         [4, 3, 2, 1, 0])
 
 
 def test_main(verbose=None):
diff --git a/Lib/unittest/loader.py b/Lib/unittest/loader.py
index e0b8585..f0cc157 100644
--- a/Lib/unittest/loader.py
+++ b/Lib/unittest/loader.py
@@ -6,23 +6,13 @@ import sys
 import traceback
 import types
 
+from functools import cmp_to_key as _CmpToKey
 from fnmatch import fnmatch
 
 from . import case, suite
 
 __unittest = True
 
-
-def _CmpToKey(mycmp):
-    'Convert a cmp= function into a key= function'
-    class K(object):
-        def __init__(self, obj):
-            self.obj = obj
-        def __lt__(self, other):
-            return mycmp(self.obj, other.obj) == -1
-    return K
-
-
 # what about .pyc or .pyo (etc)
 # we would need to avoid loading the same tests multiple times
 # from '.py', '.pyc' *and* '.pyo'