diff -r 39019673aa8d Lib/distutils/tests/test_build_ext.py
--- a/Lib/distutils/tests/test_build_ext.py	Sat Jun 28 01:19:11 2014 +0200
+++ b/Lib/distutils/tests/test_build_ext.py	Sat Jun 28 15:02:52 2014 -0400
@@ -140,6 +140,8 @@
         self.assertIn(lib, cmd.rpath)
         self.assertIn(incl, cmd.include_dirs)
 
+    @unittest.skipUnless(sysconfig._python_build(),
+        'test irrelevant for an installed Python')
     def test_optional_extension(self):
 
         # this extension will fail, but let's ignore this failure
@@ -287,6 +289,8 @@
         cmd.run()
         self.assertEqual(cmd.compiler, 'unix')
 
+    @unittest.skipUnless(sysconfig._python_build(),
+        'test irrelevant for an installed Python')
     def test_get_outputs(self):
         tmp_dir = self.mkdtemp()
         c_file = os.path.join(tmp_dir, 'foo.c')