def test_randprime(): random.seed(1234) assert randprime(2, 3) == 2 assert randprime(1, 3) == 2 assert randprime(3, 5) == 3 pytest.raises(ValueError, lambda: randprime(20, 22)) for a in [100, 300, 500, 250000]: for b in [100, 300, 500, 250000]: p = randprime(a, a + b) assert a <= p < (a + b) and isprime(p) assert randprime(70, 7) is None