Question

由于某种原因，在单元测试中执行的方法内的循环不止一次被执行。因此，我得到ConcurrentModificationException。为了简化，方法循环遍历对象，使用Runnable参数对每个对象执行其他方法。这在部署应用程序时工作正常，但在单元测试期间，循环执行多次，我收到错误。

代码示例：

@RunWith(JukitoRunner.class)
public class MyTest {

    @Inject
    MainService mainService;

    @Test
    public void testMain(){
        mainService.setData(mainService.getSelectedData());
    }
}

public class MainService {

    List<Data> data = new ArrayList<Data>();

    List<Field> fields = new ArrayList<Field>();

    public MainService(){
        /* this.fields is filled here*/
        data.add(/*data obj*/);
        data.add(/*data obj*/);
        data.add(/*data obj*/);
    }

    public List<Data> getSelectedData(){
        /* alghoritm to filter data */
        return data; /*returns List with 1 and 2nd data objects from this.data*/
    }
    private void deleteEl(Field field, Runnable callback){
        fields.remove(field);
        for (ListIterator<Data> i = data.listIterator(); i.hasNext();) {
            Data data = i.next();
            if(data.something()) i.remove();
        }

        if (callback != null) {
            callback.run();
        }
    }

    public void setData(List<Data> selected){
        for(Field field : fields){// checked with debug, this gets executed more than once, why?! It should run only once. ConcurrentModificationException gets thrown here.
            if(field instanceof Object){
                deleteEl(field, new Runnable(){
                    @Override
                    public void run(){
                        create(selected); //won't post create() code, since even commenting this, does not help. Error persists
                    }
                })
            }
        }
    }

}

Answer 1

发生异常是因为您在迭代字段列表fields时从deleteEl列表中删除了一个字段（for(Field field : fields)方法中的第一行）。

顺便说一下。我假设(field instanceof Object)的检查总是返回true。

单元测试循环不止一次执行

1 个答案: