def test_diff(self):
self.assertEqual(lD("thought","fought"),2)
self.assertEqual(lD("cats","mats"),1)
self.assertEqual(lD("threw","flew"),3)
def test_empty(self):
self.assertEqual(lD("",""),0)
self.assertEqual(lD("astfgl",""),6)
self.assertEqual(lD("","astfgl"),6)
def test_equal(self):
self.assertEqual(lD("astfgl","astfgl"),0)
self.assertEqual(lD("foobar","foobar"),0)
