assertEquals(Collections.<String, Integer>emptyMap(), copy);
    assertSame(copy, ImmutableBiMap.copyOf(copy));
    assertSame(ImmutableBiMap.of(), copy);
  }

  public void testCopyOfSingletonMap() {
    ImmutableBiMap<String, Integer> copy = ImmutableBiMap.copyOf(singletonMap("one", 1));
    assertMapEquals(copy, "one", 1);
    assertSame(copy, ImmutableBiMap.copyOf(copy));
  }

    assertEquals(Collections.<String, Integer>emptyMap(), copy);
    assertSame(copy, ImmutableSortedMap.copyOf(copy));
    assertSame(Ordering.natural(), copy.comparator());
  }

  public void testCopyOfSingletonMap() {
    ImmutableSortedMap<String, Integer> copy = ImmutableSortedMap.copyOf(singletonMap("one", 1));
    assertMapEquals(copy, "one", 1);
    assertSame(copy, ImmutableSortedMap.copyOf(copy));

        ImmutableMap.copyOf(Collections.<String, Integer>emptyMap());
    assertEquals(Collections.<String, Integer>emptyMap(), copy);
    assertSame(copy, ImmutableMap.copyOf(copy));
  }

  public void testCopyOfSingletonMap() {
    ImmutableMap<String, Integer> copy = ImmutableMap.copyOf(singletonMap("one", 1));
    assertMapEquals(copy, "one", 1);
    assertSame(copy, ImmutableMap.copyOf(copy));
  }