processor_subdir=tmpdir,
            msg=None,
        )
        dag1_sla1 = SlaCallbackRequest(
            full_filepath="/green_eggs/ham/file1.py",
            dag_id="dag1",
            processor_subdir=tmpdir,
        )
        dag1_sla2 = SlaCallbackRequest(
            full_filepath="/green_eggs/ham/file1.py",
            dag_id="dag1",
            processor_subdir=tmpdir,
        )
        dag2_req1 = DagCallbackRequest(
            full_filepath="/green_eggs/ham/file2.py",
            dag_id="dag2",
            run_id="run1",
            is_failure_callback=False,
            processor_subdir=tmpdir,
            msg=None,
        )
        
        manager._add_callback_to_queue(dag1_req1)
        manager._add_callback_to_queue(dag1_sla1)
        manager._add_callback_to_queue(dag2_req1)
        
        assert manager._file_path_queue == collections.deque(
            [dag2_req1.full_filepath, dag1_req1.full_filepath]
        )
        assert set(manager._callback_to_execute.keys()) == {dag1_req1.full_filepath, dag2_req1.full_filepath}