### Question:
VFSPipelineExecutorRegistry extends InMemoryPipelineExecutorRegistry { @Override public void deregister(final String taskId) { checkNotNull("taskId", taskId); final Path path = buildTracePath(taskId); registryHelper.deleteBatch(path); super.deregister(taskId); } VFSPipelineExecutorRegistry(); @Inject  VFSPipelineExecutorRegistry(final VFSRegistryHelper registryHelper); @PostConstruct void init(); @Override void register(final PipelineExecutorTrace trace); @Override void deregister(final String taskId);  }### Answer:
@Test @Override public void testDeregister() { prepareTargetPath(); pipelineExecutorRegistry.register(trace); PipelineExecutorTrace result = pipelineExecutorRegistry.getExecutorTrace(PIPELINE_EXECUTION_ID); assertEquals(trace, result); pipelineExecutorRegistry.deregister(PIPELINE_EXECUTION_ID); verify(registryHelper, times(1)).deleteBatch(traceTargetPath); result = pipelineExecutorRegistry.getExecutorTrace(PIPELINE_EXECUTION_ID); assertNull(result); }