def test_start_with_minus(): string = {'exp': '-2 + 2 = 0'} assert transformation( '{exp}'.format(**string)) == 'minus two plus two equals zero'
def test_one_long_function(): string = {'exp': '-8 + 6 / 2 * 2 = -2'} assert transformation( '{exp}'.format(**string) ) == 'minus eight plus six divide two multiply two equals minus two'
def test_task_example(): string = {'exp': '3 + 7 = 10'} assert transformation( '{exp}'.format(**string)) == 'three plus seven equals ten'
def test_has_alpha(): string = {'exp': '3 * a = 9'} assert transformation('{exp}'.format(**string)) == 'invalid input.'
def test_invalid_function(): string = {'exp': '3 ** 3 = 9'} assert transformation('{exp}'.format(**string)) == 'invalid input.'
def test_random_space(): string = {'exp': ' 3+ 7= 10 '} assert transformation( '{exp}'.format(**string)) == 'three plus seven equals ten'