### Question:
DefaultFileNameBuilder extends AbstractFileNameBuilder { @Override public String build() { ResourceType resourceType = null; if (metaData != null) { resourceType = metaData.getResourceType(); } String id = resourceIdentifier.getIdentifier(resourceType); clear(); return id; } DefaultFileNameBuilder(); DefaultFileNameBuilder withMetaData(ResourceMetaData metaData); DefaultFileNameBuilder withStage(When when); DefaultFileNameBuilder withResourceIdentifier(ResourceIdentifier<ResourceType> resourceIdentifier); @Override String build(); @Override DefaultFileNameBuilder clear();  }### Answer:
@Test public void emptyBuildTest() { UUID.fromString(fileNameBuilder.build()); }