@Test
    public void shouldNotBeEmpty() {
        final TraverserSet<String> ts = traverserSetMaker.get();
        ts.add(makeTraverser("test", 1));
        assertThat(ts.isEmpty(), is(false));
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/process/traversal/traverser/util/TraverserSetImplementationTest.java