CollectionFeature.SERIALIZABLE,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    return suite;
  }

  // Creation tests

  public void testEmptyBuilder() {
    ImmutableMap<String, Integer> map = new Builder<String, Integer>().buildOrThrow();
    assertEquals(Collections.<String, Integer>emptyMap(), map);
  }

  public void testSingletonBuilder() {