assertEquals(3, result.length);
        assertEquals("a", result[0]);
        assertEquals("b", result[1]);
        assertEquals("c", result[2]);
    }

    public void test_distinct_withNullElements() {
        // Test distinct with null elements
        String[] input = new String[] { "a", null, "b", null, "a" };
        String[] result = invokeDistinct(input);
        assertEquals(3, result.length);