### Question:
ReflectionHelper { static Sink<Object> getSinkOrFail(String name) { Sink<Object> sink = FluidRegistry.sink(Objects.requireNonNull(name)); if (sink == null) { throw new IllegalArgumentException("Unable to find the sink " + name); } return sink; } private  ReflectionHelper(); static void set(Object mediator, Field field, Object source); static void invokeFunction(Object mediator, Method method); static void invokeTransformationMethod(Object mediator, Method method); static Object getSourceToInject(Class<?> clazz, Type type, Source<Object> source); static void inject(Object mediator);  }### Answer:
@Test public void testGettingAMissingSink() { FluidRegistry.register("my-sink", Sink.list()); Sink<Object> sink = ReflectionHelper.getSinkOrFail("my-sink"); assertThat(sink).isNotNull(); try { ReflectionHelper.getSinkOrFail("missing"); fail("The sink should be missing"); } catch (IllegalArgumentException e) { } }