def test_ratio_of_doubled_values(self):
        self.assertAlmostEqualOnAllArrayTypes(
            percentage_of_reoccurring_values_to_all_values, [1, 1, 2, 3, 4], 0.25
        )
        self.assertAlmostEqualOnAllArrayTypes(
            percentage_of_reoccurring_values_to_all_values, [1, 1.5, 2, 3], 0
        )
        self.assertAlmostEqualOnAllArrayTypes(
            percentage_of_reoccurring_values_to_all_values, [1], 0
        )
        self.assertAlmostEqualOnAllArrayTypes(
            percentage_of_reoccurring_values_to_all_values,
            [1.111, -2.45, 1.111, 2.45],
            1.0 / 3.0,
        )
        self.assertIsNanOnAllArrayTypes(
            percentage_of_reoccurring_values_to_all_values, []
        )