@Test
public void testOptionalString() {

    TypeLiteral<List<String>> listOfStringTypeLiteral = new TypeLiteral<List<String>>() {
    };
    ConversionContext context = new ConversionContext.Builder("testOptionalString", listOfStringTypeLiteral).build();
    final Optional<String> result = new OptionalConverter().convert("astring", context);
    assertThat(result).isNotNull();
    assertThat(result.isPresent()).isTrue();
    assertThat(result.get()).isEqualTo("astring");
}