@Test
public void testSetLevels() {

    // przypadki testowe
    String[][] tests = {
        {"A", "B", "C"},
        {"A", "B", null},
        {"A", null, null},
        {null, null, null},
        {},
        null
    };
    // oczekiwany rezultat
    String[][] expected = {
        {"A", "B", "C"},
        {"A", "B"},
        {"A"},
        {},
        {},
        {}
    };
    // testy
    for (int i = 0; i < tests.length; i++) {
        String[] levels = tests[i];
        String[] getlevels = expected[i];
        PreparedEntry entry = new PreparedEntry(parameterEntry().withLevels(levels).build());
        // weryfikacja
        assertArrayEquals(getlevels, entry.getLevels());
    }
}