def test_bad_type(self):
     """Test non string arguments."""
     with self.assertRaises(TypeError):
         self.assertFalse(ishex(0xff))
     with self.assertRaises(TypeError):
         self.assertFalse(ishex(True))
 def test_hex_literal(self):
     """Test hex literal. It uses non-hex char - 'x'."""
     self.assertFalse(ishex('0xff'))
 def test_empty(self):
     """Test empty string."""
     self.assertTrue(ishex(''))
 def test_failing(self):
     """Test non-hexes."""
     self.assertFalse(ishex('g'))
     self.assertFalse(ishex('5x'))
 def test_good(self):
     """Test actual hexes."""
     self.assertTrue(ishex('1'))
     self.assertTrue(ishex('a'))
     self.assertTrue(ishex('5b'))
     self.assertTrue(ishex('1234567890abcdef'))