### Question:
ContainerFeatureSetResponseFilter implements ContainerResponseFilter { @Override public void filter(final ContainerRequestContext requestContext, final ContainerResponseContext responseContext) throws IOException { FeaturesContextHolder.clear(); }  @Override void filter(final ContainerRequestContext requestContext, final ContainerResponseContext responseContext);  }### Answer:
@Test public void shouldClearPrincipal_onFilter() throws Exception { mockStatic(FeaturesContextHolder.class); final ContainerRequestContext mockContainerRequestContext = mock(ContainerRequestContext.class); final ContainerResponseContext mockContainerResponseContext = mock(ContainerResponseContext.class); final ContainerFeatureSetResponseFilter containerFeatureSetResponseFilter = new ContainerFeatureSetResponseFilter(); containerFeatureSetResponseFilter.filter(mockContainerRequestContext, mockContainerResponseContext); verifyStatic(FeaturesContextHolder.class); FeaturesContextHolder.clear(); }