ScalaTest：了解测试执行顺序

Question

我很努力地理解为什么我的设置 - 拆卸过程不像我在ScalaTest中所期望的那样工作。基本上，我的测试代码如下：

class UserManagerTest extends FlatSpec with ManagerBehaviors[User, UserDAO] { 

    "An entity manager" should behave like allFindingManager(UserManager) 

    "An entity manager" should behave like countingManager(UserManager) 
} 


trait ManagerBehaviors[T <: IEntity, D <: AbstractDAO[T]] { 

this: FlatSpec => 

    private def withClearDB(entityManager: BasicManager[T, D], testFunction:() => Unit) = { 
    try { 
     clearDB(entityManager) 
     testFunction() 
    } finally { 
     clearDB(entityManager) 
    } 
    } 

    private def clearDB(manager: BasicManager[T, D]) = { 
    manager.all match { 
     case Some(entities) => for (entity <- entities) manager.remove(entity.getId) 
    } 
    } 

    def allFindingManager(manager: BasicManager[T, D]) { 
    withClearDB(manager, 
    () => it should "properly return all elements in the database for the entity" in { 

     // Add 10 entities to the database 
     for (i <- 1 to 10) manager.persist(manager.defaultEntity) 

     manager.all match { 
      case Some(entities) => assert(entities.length == 10) 
      case None => fail() 
     } 
     }) 
    } 

    def countingManager(manager: BasicManager[T, D]) { 
    withClearDB(manager, 
    () => it should "properly count the number of entities managed" in { 

     // Add 10 entities to the database 
     for (i <- 1 to 10) manager.persist(manager.defaultEntity) 

     assert(manager.count == 10) 
     }) 
    } 
} 

我想到的是下面的顺序：

1. clearDB

2. allFindingManager

3. clearDB

4. clearDB

5. countingManager

6. clearDB

当单独运行，测试按预期工作 - 数据库是在启动时被清除，留下空当测试结束。

但是，运行整个UserManagerTest类时，由于某种原因失败，出现以下：

org.scalatest.exceptions.TestFailedException: 20 did not equal 10 

这样做的原因是，不知何故，该测试被称为对方右后无间断clearDB调用。我无能为力，为什么会发生这种情况。

当使用调试器并在finally块内放置断点时，发现发生了什么的可能线索：此块确实运行了两次，如预期的那样，但是这发生在BEFORE（！）测试方法执行之前，这使得没有任何意义：

1. clearDB

2. clearDB

3. clearDB

4. clearDB

5. allFindingManager

6. countingManager

谁能帮助我阐明这一些轻？

Answer 1

如果更改

def countingManager(manager: BasicManager[T, D]) { 
    withClearDB(manager, 
    () => it should "properly ..." in { 

     // Add 10 entities to the database 
     for (i <- 1 to 10) manager.persist(manager.defaultEntity) 

     assert(manager.count == 10) 
    }) 
} 

到

def countingManager(manager: BasicManager[T, D]) { 

    it should "properly ..." in withClearDB(manager, 
    () => { 
     // Add 10 entities to the database 
     for (i <- 1 to 10) manager.persist(manager.defaultEntity) 

     assert(manager.count == 10) 
    } 
) 

} 

，并同样在其他功能，则执行顺序将会像你期望的那样。