from fuel import convert, gauge

def main():
    test_convert()
    test_gauge()
    test_value_error()
    test_zero_division_error()

def test_convert():
    assert convert("0/4") == 0
    assert convert("1/4") == 25
    assert convert("4/4") == 100

def test_value_error():
    try:
        convert("5/4")
    except ValueError:
        pass
    else:
        raise Exception("ValueError not raised with y>x")


def test_zero_division_error():
    try:
        convert("5/0")
    except ZeroDivisionError:
        pass
    else:
        raise Exception("ZeroDivisionError not raised with y = 0")


def test_gauge():
    assert gauge(100) == 'F'
    assert gauge(99) == 'F'
    assert gauge(0) == 'E'
    assert gauge(1) == 'E'
    assert gauge(27) == '27%'


if __name__ == '__main__':
    main()