def test_gen_numbers_with_difference(self):
gen = NumPrimeGenerator([2, 7, 13, 29])
random.seed(23456)
maxval = 2000
success_count = 0
for i in range(1000, 1500):
with self.subTest(i=i):
pair = gen.gen_numbers_with_difference(maxval, i, 10)
if pair is not None:
self.assertEqual(len(pair), 2)
success_count += 1
self.assertTrue(gen.is_valid(pair[0], maxval))
self.assertTrue(gen.is_valid(pair[1], maxval))
self.assertEqual(pair[0] - pair[1], i)
# At least some reasonable number of success
self.assertGreaterEqual(success_count, 50)
