improve URLWrapper comparison

* speed up via reduced slugify calls (only call when needed)
* fix __repr__ to not contain str, should call repr on name
* add test_urlwrappers and move URLWrappers tests there
  * add new equality test
* cleanup header

additionally:
* Content is now decorated with python_2_unicode_compatible
  instead of treating __str__ differently
* better formatting for test_article_metadata_key_lowercase
  to actually output the conflict instead of a non descriptive
  error

pelican/tests/test_urlwrappers.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from pelican.urlwrappers import URLWrapper, Tag, Category
+from pelican.tests.support import unittest
+
+class TestURLWrapper(unittest.TestCase):
+    def test_ordering(self):
+        # URLWrappers are sorted by name
+        wrapper_a = URLWrapper(name='first', settings={})
+        wrapper_b = URLWrapper(name='last', settings={})
+        self.assertFalse(wrapper_a > wrapper_b)
+        self.assertFalse(wrapper_a >= wrapper_b)
+        self.assertFalse(wrapper_a == wrapper_b)
+        self.assertTrue(wrapper_a != wrapper_b)
+        self.assertTrue(wrapper_a <= wrapper_b)
+        self.assertTrue(wrapper_a < wrapper_b)
+        wrapper_b.name = 'first'
+        self.assertFalse(wrapper_a > wrapper_b)
+        self.assertTrue(wrapper_a >= wrapper_b)
+        self.assertTrue(wrapper_a == wrapper_b)
+        self.assertFalse(wrapper_a != wrapper_b)
+        self.assertTrue(wrapper_a <= wrapper_b)
+        self.assertFalse(wrapper_a < wrapper_b)
+        wrapper_a.name = 'last'
+        self.assertTrue(wrapper_a > wrapper_b)
+        self.assertTrue(wrapper_a >= wrapper_b)
+        self.assertFalse(wrapper_a == wrapper_b)
+        self.assertTrue(wrapper_a != wrapper_b)
+        self.assertFalse(wrapper_a <= wrapper_b)
+        self.assertFalse(wrapper_a < wrapper_b)
+
+    def test_equality(self):
+        tag = Tag('test', settings={})
+        cat = Category('test', settings={})
+
+        # same name, but different class
+        self.assertNotEqual(tag, cat)
+
+        # should be equal vs text representing the same name
+        self.assertEqual(tag, u'test')
+
+        # should not be equal vs binary
+        self.assertNotEqual(tag, b'test')
+
+        # Tags describing the same should be equal
+        tag_equal = Tag('Test', settings={})
+        self.assertEqual(tag, tag_equal)
+
+        cat_ascii = Category('指導書', settings={})
+        self.assertEqual(cat_ascii, u'zhi-dao-shu')