.singleton("urlConvertHelper", UrlConvertHelper.class).singleton("intervalController", DefaultIntervalController.class)
                .singleton("sitemapsHelper", SitemapsHelper.class).singleton("logHelper", LogHelperImpl.class)
                .singleton("encodingHelper", EncodingHelper.class).singleton("contentLengthHelper", ContentLengthHelper.class)
                .singleton("mimeTypeHelper", MimeTypeHelperImpl.class)

    if (supportsRemove) {
      int initialSize = map.size();
      assertTrue(keys.removeAll(singleton(key)));
      assertEquals(initialSize - 1, map.size());
      assertFalse(map.containsKey(key));
    } else {
      assertThrows(UnsupportedOperationException.class, () -> keys.removeAll(singleton(key)));
    }
    assertInvariants(map);
  }

  public void testKeySetRetainAll() {

    assertEquals(ImmutableRangeSet.<Integer>all(), rangeSet.complement());
    assertFalse(rangeSet.contains(0));
    assertFalse(rangeSet.intersects(Range.singleton(0)));
    assertFalse(rangeSet.encloses(Range.singleton(0)));
    assertTrue(rangeSet.enclosesAll(rangeSet));
    assertTrue(rangeSet.isEmpty());
  }

  public void testAll() {

    assertEquals(singleton("bar"), set);
    set.clear();
    assertTrue(set.isEmpty());
    assertEquals(singleton("foo"), sortedTable.rowKeySet());
  }

  public void testRowKeySetTailSet() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Set<String> set = sortedTable.rowKeySet().tailSet("cat");
    assertEquals(singleton("foo"), set);
    set.clear();

            }
        }
    }

    @Singleton
    @Named(Lifecycle.CLEAN)
    @SuppressWarnings("unused")
    static class CleanLifecycleProvider extends BaseLifecycleProvider {
        CleanLifecycleProvider() {
            super(Lifecycle.CLEAN);
        }
    }

    @Singleton
    @Named(Lifecycle.DEFAULT)
    @SuppressWarnings("unused")

    Collection<String> c = MinimalCollection.of("a");
    Set<String> set = copyOf(c);
    assertEquals(singleton("a"), set);
  }

  public void testCopyOf_collection_oneElementRepeated() {
    Collection<String> c = MinimalCollection.of("a", "a", "a");
    Set<String> set = copyOf(c);
    assertEquals(singleton("a"), set);
  }

  public void testCopyOf_collection_general() {

    assertFalse(entries.contains(Maps.immutableEntry("foo", singleton(2))));
    assertFalse(entries.remove(Maps.immutableEntry("foo", singleton(2))));
    assertTrue(map.containsKey("foo"));
    assertTrue(entries.contains(Maps.immutableEntry("foo", singleton(1))));
    assertTrue(entries.remove(Maps.immutableEntry("foo", singleton(1))));
    assertFalse(map.containsKey("foo"));
  }

                    checkArgument(elements.length == 1);
                    return Sets.union(Sets.<String>newHashSet(elements), newHashSet(elements));
                  }
                })
            .named("singleton U itself")
            .withFeatures(CollectionSize.ONE, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(

            new TestStringSetGenerator() {
              @Override
              public Set<String> create(String[] elements) {
                return singleton(elements[0]);
              }
            })
        .named("singleton")
        .withFeatures(
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ONE)

            new TestStringSetGenerator() {
              @Override
              public Set<String> create(String[] elements) {
                return singleton(elements[0]);
              }
            })
        .named("singleton")
        .withFeatures(
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ONE)