WebComponentConfigurationRegistry implements Serializable { public Set<WebComponentConfiguration<? extends Component>> getConfigurations() { lock(); try { return Collections .unmodifiableSet(new HashSet<>(configurationMap.values())); } finally { unlock(); } } protected  WebComponentConfigurationRegistry(); Optional<WebComponentConfiguration<? extends Component>> getConfiguration(
            String tag); @SuppressWarnings("unchecked") Set<WebComponentConfiguration<T>> getConfigurationsByComponentType(
            Class<T> componentClass); boolean setConfigurations(
            Set<WebComponentConfiguration<? extends Component>> configurations); boolean hasConfigurations(); Optional<T> getEmbeddedApplicationAnnotation(
            Class<T> type); Set<WebComponentConfiguration<? extends Component>> getConfigurations(); void setShadowDomElements(List<Element> elements); List<Element> getShadowDomElements(); static WebComponentConfigurationRegistry getInstance(
            VaadinContext context);  }
@Test public void getConfigurations_uninitializedReturnsEmptySet() { WebComponentConfigurationRegistry uninitializedRegistry = new WebComponentConfigurationRegistry(); Set<?> set = uninitializedRegistry.getConfigurations(); Assert.assertEquals("Configuration set should be empty", 0, set.size()); }