Converter<String, TestEnum> converter = Enums.stringConverter(TestEnum.class);
    assertThrows(IllegalArgumentException.class, () -> converter.convert("xxx"));
  }

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

    assertThat(Doubles.stringConverter().reverse().convert(null)).isNull();
  }

  @GwtIncompatible // Double.toString returns different value in GWT.
  public void testStringConverter_reverse() {
    Converter<String, Double> converter = Doubles.stringConverter();
    assertThat(converter.reverse().convert(1.0)).isEqualTo("1.0");
    assertThat(converter.reverse().convert(0.0)).isEqualTo("0.0");

  public void testStringConverter_nullConversions() {
    assertThat(Ints.stringConverter().convert(null)).isNull();
    assertThat(Ints.stringConverter().reverse().convert(null)).isNull();
  }

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

    assertThat(Shorts.stringConverter().convert(null)).isNull();
    assertThat(Shorts.stringConverter().reverse().convert(null)).isNull();
  }

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