Delegate expression does not work in unit test

Hi Camunda Team,
I was trying to run the junit test i am getting below exception when i use delegateexpression, but when use java class its working fine

exception:
org.camunda.bpm.engine.ProcessEngineException: One of the attributes ‘class’, ‘delegateExpression’, ‘type’, or ‘expression’ is mandatory on serviceTask. | edu_workflow_errorhandling.bpmn | line 11 | column 126

@Deployment(resources=“edu_workflow_errorhandling.bpmn”)
public void testProcessRetryLogic() {
RuntimeService runtimeService = processEngineRule.getRuntimeService();
}
Using spring application with camunda, could some suggest, what could be the issue?

Same thing is working fine, when deployed on tomcat, only issue with junit

Please post the BPMN XML and the version of the process engine you use in the test.