JUNIT 测试时出现 java.lang.StackOverflowError答案

【问题标题】：java.lang.StackOverflowError while JUNIT testingJUNIT 测试时出现 java.lang.StackOverflowError
【发布时间】：2023-03-06 21:40:01
【问题描述】：

我想学习如何创建单元测试。我以前从未这样做过，所以我阅读了一些教程，并尝试测试我的 addTraining to Day 方法。但是当我做我的测试方法时（imo我用正确的方式写了这个）我有java.lang.StackOverflowError。有人可以帮我吗？我不知道该怎么办。

这是我要测试的方法，我想我必须创建三个案例来测试这个对吗？

    public void addTraining(String userId, Training training, LocalDate localDate) {
      Day activityBoardDay = getActivityBoardDay(localDate, userId);
      List<Training> trainingList = activityBoardDay.getTrainings();
      if (trainingList == null || trainingList.isEmpty()) {
        activityBoardDay.setTrainings(Collections.singletonList(training));
      } else {
        trainingList.add(training);
        activityBoardDay.setTrainings(trainingList);
      }
      activityBoardDay.setTrainings(trainingList);
  }

这是我的测试课：

@RunWith(MockitoJUnitRunner.class)
public class ActivitiesServiceTest {


@Mock
private DbService databaseControllerMock;


private ActivitiesService activitiesService;

private String userId = "test";


@Before
public void setUp() throws Exception {
    activitiesService = new ActivitiesService(databaseControllerMock);
}

@After
public void tearDown() throws Exception {
    getDayWithNulls().setTrainings(null);
    getDayWithNulls().setMeasurements(null);
    getDayWithNulls().setTrainingCycles(null);
    getDayWithNulls().setDiets(null);
    getDayWithNulls().setMeals(null);
    getDayWithNulls().setLocalDate(LocalDate.now());
}


@Test
public void addTraining() {
    //WITH NULLS
    getDayWithNulls();
    activitiesService.addTraining(userId, getTrainingForTest(), LocalDate.now());
    Assert.assertEquals(getDayWithNulls(), expectedDayWithAddedTrainingToNulls());

}


private Exercise getSquatExcercise() {
    Exercise exercise = new Exercise();
    exercise.setId("1");
    exercise.setName("Squat");
    exercise.setDescription("How to squat properly?");
    exercise.setCalories(3);
    exercise.setNotes("Calories per one squat");
    return exercise;
}

private Exercise getRunExcercise() {
    Exercise exercise = new Exercise();
    exercise.setId("2");
    exercise.setName("Run");
    exercise.setDescription("How to run properly?");
    exercise.setCalories(3);
    exercise.setNotes("Calories per one running session");
    return exercise;
}

private Exercise getWalkExcercise() {
    Exercise exercise = new Exercise();
    exercise.setId("3");
    exercise.setName("Walk");
    exercise.setDescription("How to walk properly?");
    exercise.setCalories(3);
    exercise.setNotes("Calories per one walking session");
    return exercise;
}

private Training getTrainingForTest() {
    Training training = new Training();
    List<Exercise> exercises = new ArrayList<>();
    exercises.add(getRunExcercise());
    exercises.add(getSquatExcercise());
    exercises.add(getWalkExcercise());
    training.setExerciseList(exercises);
    return training;
}

private Day getDayWithNulls() {
    getDayWithNulls().setTrainings(null);
    getDayWithNulls().setMeasurements(null);
    getDayWithNulls().setTrainingCycles(null);
    getDayWithNulls().setDiets(null);
    getDayWithNulls().setMeals(null);
    getDayWithNulls().setLocalDate(LocalDate.now());
    return getDayWithNulls();
}

private Day expectedDayWithAddedTrainingToNulls() {
    expectedDayWithAddedTrainingToNulls().setTrainings(Collections.singletonList(getTrainingForTest()));
    expectedDayWithAddedTrainingToNulls().setMeasurements(null);
    expectedDayWithAddedTrainingToNulls().setTrainingCycles(null);
    expectedDayWithAddedTrainingToNulls().setDiets(null);
    expectedDayWithAddedTrainingToNulls().setMeals(null);
    expectedDayWithAddedTrainingToNulls().setLocalDate(LocalDate.now());
    return expectedDayWithAddedTrainingToNulls();
}
}

【问题讨论】：

堆栈跟踪在哪里？
@Eran in line getDayWithNulls().setTrainings(null);

标签： java unit-testing testing junit

【解决方案1】：

getDayWithNulls() 正在调用自己，这会导致无限递归和StackOverflowError。 getDayWithNulls() 可能应该调用一些其他方法来生成它返回的 Day 实例。

private Day getDayWithNulls() {
    Day day = ... // call some method to create a Day instance,
                  // but don't call getDayWithNulls() !

    day.setTrainings(null);
    day.setMeasurements(null);
    day.setTrainingCycles(null);
    day.setDiets(null);
    day.setMeals(null);
    day.setLocalDate(LocalDate.now());

    return day;
}

【讨论】：