### Question:
MetricsFactoryResolver { public MetricsFactory resolve() { for (MetricsFactoryService metricsFactoryService : serviceLoader) { MetricsFactory metricsFactory = metricsFactoryService.load(); if (metricsFactory != null) { return metricsFactory; } } throw new IllegalStateException("No MetricsFactory could be loaded!"); } private  MetricsFactoryResolver(); MetricsFactory resolve(); static final MetricsFactoryResolver INSTANCE; }### Answer:
@Test public void testResolve() { MetricsFactoryResolver resolver = MetricsFactoryResolver.INSTANCE; MetricsFactory metricsFactory = resolver.resolve(); assertNotNull(metricsFactory); }