.addEqualityGroup(Equivalence.equals().wrap("hello"))
        .addEqualityGroup(Equivalence.equals().<@Nullable Object>wrap(null))
        .testEquals();
  }

  public void testWrap_get() {
    String test = "test";
    Wrapper<String> wrapper = LENGTH_EQUIVALENCE.wrap(test);
    assertThat(wrapper.get()).isSameInstanceAs(test);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester