def test_factorial(number, expected):
assert type(factorial(number)) == int
assert factorial(number) == expected
def test_three():
assert factorial(3) == 3 * 2
def test_identical_factorials(x):
assert factorial(x) == x
def test_one_hundred():
assert factorial(100) == 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
def test_five():
assert factorial(5) == 5 * 4 * 3 * 2
def test_four():
assert factorial(4) == 4 * 3 * 2