def test_parse_a_single_number(self): eq_(1, calculate("1"))
def test_add_two_numbers(self): eq_(10, calculate("8+2"))
def test_numbers_can_have_at_most_one_decimal_point(self): calculate("2.7.2")
def test_parse_a_negative_number(self): eq_(-15, calculate("-15"))
def test_parse_a_decimal_number(self): eq_(3.141, calculate("3.141"))