@Test
void install() {

    final Transform<Integer, String> transform = (g, i) -> Optional.of(Integer.toString(i));
    instance.install(Integer.class, String.class, () -> transform);
    final StandardGenerator generator = new StandardGenerator(new DefaultDependencyManager(), instance);
    final Optional<String> result = generator.on(1);
    assertEquals("1", result.orElseThrow(NoSuchElementException::new));
}