Move Python 2.6 exception into specific test, capturing that the expected...

Move Python 2.6 exception into specific test, capturing that the expected order is different on Python 2.6, not because of the lack of OrderedDict, but because of different behavior in RawConfigParser. Ref #553.

setuptools/tests/test_egg_info.py

@@ -87,12 +87,12 @@ class TestEggInfo(object):
         self._validate_content_order(content, expected_order)
 
     @staticmethod
-    def _validate_content_order(content, expected_order):
-        if sys.version_info < (2, 7):
-            # order cannot be guaranteed on Python 2.6
-            return
-
-        pattern = '.*'.join(expected_order)
+    def _validate_content_order(content, expected):
+        """
+        Assert that the strings in expected appear in content
+        in order.
+        """
+        pattern = '.*'.join(expected)
         flags = re.MULTILINE | re.DOTALL
         assert re.search(pattern, content, flags)
 
@@ -120,6 +120,12 @@ class TestEggInfo(object):
         assert 'tag_svn_revision = 0' in content
 
         expected_order = 'tag_build', 'tag_date', 'tag_svn_revision'
+
+        if sys.version_info < (2, 7):
+            # On Python 2.6, config gets overridden, retaining order
+            # from the dict.
+            expected_order = dict.fromkeys(expected_order).keys()
+
         self._validate_content_order(content, expected_order)
 
     def test_egg_base_installed_egg_info(self, tmpdir_cwd, env):