def test_can_multiply_two_numbers(self):
input_data = ["2 4 *"]
expected = [8]
self.assertEqual(expected, evaluate(input_data))
def test_errors_if_there_is_nothing_on_the_stack(self):
input_data = ["*"]
with self.assertRaises(StackUnderflowError):
evaluate(input_data)
def test_is_case_insensitive(self):
input_data = ["1 2 Drop"]
expected = [1]
self.assertEqual(expected, evaluate(input_data))
def test_errors_if_executing_a_non_existent_word(self):
input_data = ["foo"]
with self.assertRaises(ValueError):
evaluate(input_data)
def test_can_add_two_numbers(self):
input_data = ["1 2 +"]
expected = [3]
self.assertEqual(expected, evaluate(input_data))
def test_multiplication_and_division(self):
input_data = ["2 4 * 3 /"]
expected = [2]
self.assertEqual(expected, evaluate(input_data))
def test_can_override_other_user_defined_words(self):
input_data = [": foo dup ;", ": foo dup dup ;", "1 foo"]
expected = [1, 1, 1]
self.assertEqual(expected, evaluate(input_data))
def test_errors_if_dividing_by_zero(self):
input_data = ["4 0 /"]
with self.assertRaises(ZeroDivisionError):
evaluate(input_data)
def test_can_consist_of_built_in_words(self):
input_data = [": dup-twice dup dup ;", "1 dup-twice"]
expected = [1, 1, 1]
self.assertEqual(expected, evaluate(input_data))
def test_execute_in_the_right_order(self):
input_data = [": countup 1 2 3 ;", "countup"]
expected = [1, 2, 3]
self.assertEqual(expected, evaluate(input_data))
def test_is_case_insensitive(self):
input_data = ["3 4 Over"]
expected = [3, 4, 3]
self.assertEqual(expected, evaluate(input_data))
def test_copies_the_second_element_if_there_are_more_than_two(self):
input_data = ["1 2 3 OVER"]
expected = [1, 2, 3, 2]
self.assertEqual(expected, evaluate(input_data))
def test_swaps_two_two_values_on_stack(self):
input_data = ["1 2 3 SWAP"]
expected = [1, 3, 2]
self.assertEqual(expected, evaluate(input_data))
def test_can_divide_two_numbers(self):
input_data = ["3 4 -"]
expected = [-1]
self.assertEqual(expected, evaluate(input_data))
def test_can_override_built_in_words(self):
input_data = [": swap dup ;", "1 swap"]
expected = [1, 1]
self.assertEqual(expected, evaluate(input_data))
def test_performs_integer_division(self):
input_data = ["8 3 /"]
expected = [2]
self.assertEqual(expected, evaluate(input_data))
def test_can_override_built_in_operators(self):
input_data = [": + * ;", "3 4 +"]
expected = [12]
self.assertEqual(expected, evaluate(input_data))
def test_errors_if_there_is_only_one_value_on_the_stack(self):
input_data = ["1 /"]
with self.assertRaises(StackUnderflowError):
evaluate(input_data)
def test_is_case_insensitive(self):
input_data = [": foo dup ;", "1 FOO"]
expected = [1, 1]
self.assertEqual(expected, evaluate(input_data))
def test_addition_and_subtraction(self):
input_data = ["1 2 + 4 -"]
expected = [-1]
self.assertEqual(expected, evaluate(input_data))
def test_cannot_redefine_numbers(self):
input_data = [": 1 2 ;"]
with self.assertRaises(ValueError):
evaluate(input_data)
def test_copies_the_top_value_on_the_stack(self):
input_data = ["1 DUP"]
expected = [1, 1]
self.assertEqual(expected, evaluate(input_data))
def test_removes_the_top_value_on_the_stack_if_it_not_the_only_one(self):
input_data = ["3 4 DROP"]
expected = [3]
self.assertEqual(expected, evaluate(input_data))
