Optional<TestEnum> result = Enums.getIfPresent(shadowTestEnum, "blibby");
    assertThat(result).isAbsent();
    return new WeakReference<>(shadowLoader);
  }

  public void testStringConverter_convert() {
    Converter<String, TestEnum> converter = Enums.stringConverter(TestEnum.class);
    assertEquals(TestEnum.CHEETO, converter.convert("CHEETO"));
    assertEquals(TestEnum.HONDA, converter.convert("HONDA"));

    }
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNulls() {
    new NullPointerTester().testAllPublicStaticMethods(Doubles.class);
  }

  public void testStringConverter_convert() {
    Converter<String, Double> converter = Doubles.stringConverter();
    assertThat(converter.convert("1.0")).isEqualTo(1.0);
    assertThat(converter.convert("0.0")).isEqualTo(0.0);

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNulls() {
    new NullPointerTester().testAllPublicStaticMethods(Ints.class);
  }

  public void testStringConverter_convert() {
    Converter<String, Integer> converter = Ints.stringConverter();
    assertThat(converter.convert("1")).isEqualTo(1);
    assertThat(converter.convert("0")).isEqualTo(0);

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNulls() {
    new NullPointerTester().testAllPublicStaticMethods(Shorts.class);
  }

  public void testStringConverter_convert() {
    Converter<String, Short> converter = Shorts.stringConverter();
    assertThat(converter.convert("1")).isEqualTo(1);
    assertThat(converter.convert("0")).isEqualTo(0);