def testAdd(self):
'''Headers.add'''
h = Headers({'key1': 'value1'})
self.assertEqual(len(h), 1)
self.assertEqual(h.keys(), ['key1'])
h.add('key2', 'value2')
self.assertEqual(len(h), 2)
self.assertSameItems(h.keys(), ['key1', 'key2'])
h.add('Key1', 'value2')
self.assertEqual(len(h), 3)
self.assertSameItems(h.keys(), ['key1', 'key2'])
