new EqualsTester()
        .addEqualityGroup(
            Equivalence.identity().onResultOf(Functions.toStringFunction()),
            Equivalence.identity().onResultOf(Functions.toStringFunction()))
        .addEqualityGroup(Equivalence.equals().onResultOf(Functions.toStringFunction()))
        .addEqualityGroup(Equivalence.identity().onResultOf(Functions.identity()))
        .testEquals();
  }

  public void testEquivalentTo() {

    assertSame(stringIdentityConverter, stringIdentityConverter.reverse());
    assertSame(STR_TO_LONG, stringIdentityConverter.andThen(STR_TO_LONG));

    assertSame(STR_VAL, stringIdentityConverter.convert(STR_VAL));
    assertSame(STR_VAL, stringIdentityConverter.reverse().convert(STR_VAL));

    assertEquals("Converter.identity()", stringIdentityConverter.toString());

      A finalAccum = scheme.result(collector, inputs);
      if (collector.characteristics().contains(Collector.Characteristics.IDENTITY_FINISH)) {
        @SuppressWarnings("unchecked") // `R` and `A` match for an `IDENTITY_FINISH`
        R result = (R) finalAccum;
        assertEquivalent(expectedResult, result);
      }

public class MapsTransformValuesTest extends AbstractMapsTransformValuesTest {
  @Override
  protected Map<String, String> makeEmptyMap() {
    return Maps.transformValues(Maps.<String, String>newHashMap(), Functions.<String>identity());
  }

  @Override
  protected Map<String, String> makePopulatedMap() {
    Map<String, Integer> underlying = Maps.newHashMap();
    underlying.put("a", 1);
    underlying.put("b", 2);

    new EqualsTester()
        .addEqualityGroup(
            Equivalence.identity().onResultOf(Functions.toStringFunction()),
            Equivalence.identity().onResultOf(Functions.toStringFunction()))
        .addEqualityGroup(Equivalence.equals().onResultOf(Functions.toStringFunction()))
        .addEqualityGroup(Equivalence.identity().onResultOf(Functions.identity()))
        .testEquals();
  }

  public void testEquivalentTo() {

  public void testIdentity_same() {
    Function<@Nullable String, @Nullable String> identity = Functions.identity();
    assertNull(identity.apply(null));
    assertSame("foo", identity.apply("foo"));
  }

  public void testIdentity_notSame() {
    Function<Long, Long> identity = Functions.identity();
    assertNotSame(new Long(135135L), identity.apply(new Long(135135L)));
  }

  @J2ktIncompatible

  public void testIdentity_same() {
    Function<@Nullable String, @Nullable String> identity = Functions.identity();
    assertNull(identity.apply(null));
    assertSame("foo", identity.apply("foo"));
  }

  public void testIdentity_notSame() {
    Function<Long, Long> identity = Functions.identity();
    assertNotSame(new Long(135135L), identity.apply(new Long(135135L)));
  }

  @J2ktIncompatible

    }

    @Override
    public int hashCode() {
      return identity;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof FreshInvocationHandler) {
        FreshInvocationHandler that = (FreshInvocationHandler) obj;
        return identity == that.identity;
      }
      return false;
    }

    @Override
    public String toString() {

    Map<String, Integer> expected = Maps.transformValues(underlying, Functions.<Integer>identity());

    assertMapsEqual(expected, expected);

    Map<String, Integer> equalToUnderlying = Maps.newTreeMap();
    equalToUnderlying.putAll(underlying);
    Map<String, Integer> map =
        Maps.transformValues(equalToUnderlying, Functions.<Integer>identity());
    assertMapsEqual(expected, map);

    map =

    assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.toStringFunction()));
  }

  public void testTransform_presentIdentity() {
    assertEquals(Optional.of("a"), Optional.of("a").transform(Functions.identity()));
  }

  public void testTransform_presentToString() {