code: @Deployment public void testQueryBySignalSubscriptionName(){
    runtimeService.startProcessInstanceByKey("catchSignal");
    Execution execution=runtimeService.createExecutionQuery().signalEventSubscriptionName("alert").singleResult();
    assertNotNull(execution);
    execution=runtimeService.createExecutionQuery().signalEventSubscriptionName("nonExisitng").singleResult();
    assertNull(execution);
    runtimeService.startProcessInstanceByKey("catchSignal");
    assertEquals(2,runtimeService.createExecutionQuery().signalEventSubscriptionName("alert").count());
  }
  