def test_value_is_true(self):
     self.assertEqual(
         prime_numbers.append_prime_numbers(True),
         "Operation cannot allow " + str(type(True)) + ", integers only.")
 def test_numbers_less_than_one5(self):
     self.assertEqual(prime_numbers.append_prime_numbers(-1000),
                      "Prime numbers exist only for positive integers")
 def test_value_is_dictionary(self):
     self.assertEqual(
         prime_numbers.append_prime_numbers({}),
         "Operation cannot allow " + str(type({})) + ", integers only.")
 def test_value_is_string(self):
     self.assertEqual(
         prime_numbers.append_prime_numbers("string"),
         "Operation cannot allow " + str(type("")) + ", integers only.")