@Test
public void testOfSet() {

    Set<String> set = ofSet();
    assertEquals(emptySet(), set);
    set = ofSet(((String[]) null));
    assertEquals(emptySet(), set);
    set = ofSet("A", "B", "C");
    Set<String> expectedSet = new LinkedHashSet<>();
    expectedSet.add("A");
    expectedSet.add("B");
    expectedSet.add("C");
    assertEquals(expectedSet, set);
}