def test_rational_number_reduce():
a = RN(12, 6)
a._reduce()
assert a.__str__() == '2/1'
b = RN(3, 12)
b._reduce()
assert a.__str__() == '1/4'
def test_rational_number_equal():
a = RN(4, 3)
b = RN(4, 3)
c = RN(5, 3)
assert a == b
assert b == a
assert not a == c
assert not c == a
assert not b == c
assert not c == b
def test_rational_number_division():
a = RN(3, 5)
b = RN(6, 5)
c = RN(1, 2)
assert a / b == c
d = RN(3, 7)
e = RN(8, 5)
f = RN(15, 56)
assert d / e == f
def test_rational_number_multiplication():
a = RN(3, 5)
b = RN(7, 5)
c = RN(21, 25)
assert a * b == c
d = RN(4, 5)
e = RN(5, 4)
f = RN(1, 1)
assert d * e == f
def test_rational_number_subtraction():
a = RN(5, 4)
b = RN(4, 4)
c = RN(1, 4)
assert a - b == c
d = RN(5, 4)
e = RN(4, 5)
f = RN(9, 20)
assert d - e == f
def test_rational_number_addition():
a = RN(4, 3)
b = RN(8, 3)
c = RN(4, 1)
assert a + b == c
d = RN(3, 4)
e = RN(3, 5)
f = RN(27, 20)
assert d + e == f
def test_rational_number_denominator_zero():
with pytest.raises(ValueError):
r = RN(7, 0)
r = RN(11, 0)