def test_first_array(self):
result = rearrange_digits([4, 6, 2, 5, 9, 8])
self.assertEqual([964, 852], result)
def test_array_with_two_elements(self):
self.assertEqual([2, 1], rearrange_digits([1, 2]))
def test_array_with_three_elements(self):
self.assertEqual([31, 2], rearrange_digits([3, 1, 2]))
def test_array_with_one_element(self):
self.assertIsNone(rearrange_digits([1]))
def test_none_array(self):
self.assertIsNone(rearrange_digits(None))
def test_second_array(self):
result = rearrange_digits([5, 4, 3, 2, 1])
self.assertEqual([531, 42], result)
def test_second_array_sorted(self):
result = rearrange_digits([1, 2, 3, 4, 5])
self.assertEqual([531, 42], result)
def test_first_array_sorted(self):
result = rearrange_digits([2, 4, 5, 6, 8, 9])
self.assertEqual([964, 852], result)