@Test
public void testTraverseWithoutObjectType() throws Exception {

  TraverseGraphByObjectsRequest request = new TraverseGraphByObjectsRequest()
          .setObjects(set("ThreatActor/Sofacy"));
  doThrow(InvalidArgumentException.class).when(objectTypeHandler).assertObjectTypeExists("ThreatActor", "type");
  assertThrows(InvalidArgumentException.class, () -> delegate.handle(request));
}