assertThat(converter.reverse().convert(5)).isEqualTo("5");
  }

  // Null-passthrough violates our nullness annotations, so we don't support it under J2KT.
  @J2ktIncompatible
  public void testNullIsPassedThrough() {
    Converter<String, String> nullsArePassed = sillyConverter(false);
    assertThat(nullsArePassed.convert("foo")).isEqualTo("forward");
    assertThat(nullsArePassed.convert(null)).isEqualTo("forward");