@Test
void getSet()
{

    Set<String> result = this.tool.getSet();
    assertNotNull(result, "Returned null instead of a set");
    assertTrue(result.isEmpty(), "Returned set wasn't initially empty");
    // Check that null values are supported
    assertFalse(result.contains(null), "null value already present in the empty set");
    assertTrue(result.add(null), "null value already present in the empty set");
    assertTrue(result.contains(null), "null value wasn't inserted in the set");
    assertFalse(result.add(null), "null value was re-inserted in the set");
    assertTrue(result.remove(null), "failed to remove null value from the set");
    assertFalse(result.contains(null), "null value present in the set after being removed");
}