### Question:
OMVolumeRemoveAclRequest extends OMVolumeAclRequest { private OzoneAcl getAcl() { return ozoneAcls.get(0); } OMVolumeRemoveAclRequest(OMRequest omRequest); @Override List<OzoneAcl> getAcls(); @Override String getVolumeName();  }### Answer:
@Test public void testValidateAndUpdateCacheSuccess() throws Exception { String volumeName = UUID.randomUUID().toString(); String ownerName = "user1"; TestOMRequestUtils.addUserToDB(volumeName, ownerName, omMetadataManager); TestOMRequestUtils.addVolumeToDB(volumeName, ownerName, omMetadataManager); OzoneAcl acl = OzoneAcl.parseAcl("user:bilbo:rwdlncxy[ACCESS]"); OMRequest addAclRequest = TestOMRequestUtils.createVolumeAddAclRequest(volumeName, acl); OMVolumeAddAclRequest omVolumeAddAclRequest = new OMVolumeAddAclRequest(addAclRequest); omVolumeAddAclRequest.preExecute(ozoneManager); OMClientResponse omClientAddResponse = omVolumeAddAclRequest.validateAndUpdateCache(ozoneManager, 1, ozoneManagerDoubleBufferHelper); OMResponse omAddAclResponse = omClientAddResponse.getOMResponse(); Assert.assertNotNull(omAddAclResponse.getAddAclResponse()); Assert.assertEquals(OzoneManagerProtocolProtos.Status.OK, omAddAclResponse.getStatus()); OMRequest removeAclRequest = TestOMRequestUtils.createVolumeRemoveAclRequest(volumeName, acl); OMVolumeRemoveAclRequest omVolumeRemoveAclRequest = new OMVolumeRemoveAclRequest(removeAclRequest); omVolumeRemoveAclRequest.preExecute(ozoneManager); String volumeKey = omMetadataManager.getVolumeKey(volumeName); OmVolumeArgs omVolumeArgs = omMetadataManager.getVolumeTable().get(volumeKey); Assert.assertNotNull(omVolumeArgs); OmOzoneAclMap aclMapBeforeRemove = omVolumeArgs.getAclMap(); Assert.assertEquals(acl, aclMapBeforeRemove.getAcl().get(0)); OMClientResponse omClientRemoveResponse = omVolumeRemoveAclRequest.validateAndUpdateCache(ozoneManager, 2, ozoneManagerDoubleBufferHelper); OMResponse omRemoveAclResponse = omClientRemoveResponse.getOMResponse(); Assert.assertNotNull(omRemoveAclResponse.getRemoveAclResponse()); Assert.assertEquals(OzoneManagerProtocolProtos.Status.OK, omRemoveAclResponse.getStatus()); OmOzoneAclMap aclMapAfterRemove = omMetadataManager .getVolumeTable().get(volumeKey).getAclMap(); Assert.assertEquals(0, aclMapAfterRemove.getAcl().size()); }