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每个测试用例后清除内存数据库

发布于 2024-11-27 14:12:38 字数 180 浏览 2 评论 0原文

我正在使用 hsqldb 来测试 Java 中的一些数据访问层。我有大约 100 个测试用例。我创建一个内存数据库，然后在表中插入一些值，以便通过我的测试用例我可以加载它，但问题是对于每个测试用例，我需要清除内存数据库，只有值而不是表。

是否可能，一件事是我需要手动删除表中的行，还有其他我可以使用的东西吗？

谢谢

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蹲在坟头点根烟 2024-12-04 14:12:38

如果您在单元测试中使用DbUnit，则可以指定DbUnit应在之前执行清理和插入操作每次测试前确保数据库内容处于有效状态。这可以通过类似于下面的方式来完成：

@Before
public void setUp() throws Exception
{
    logger.info("Performing the setup of test {}", testName.getMethodName());
    IDatabaseConnection connection = null;
    try
    {
        connection = getConnection();
        IDataSet dataSet = getDataSet();
        //The following line cleans up all DbUnit recognized tables and inserts and test data before every test.
        DatabaseOperation.CLEAN_INSERT.execute(connection, dataSet);
    }
    finally
    {
        // Closes the connection as the persistence layer gets it's connection from elsewhere
        connection.close();
    }
}

请注意，始终建议在 @Before 设置方法中执行任何设置活动，而不是在 @After 中> 拆解方法。后者表明您正在正在测试的方法中创建新的数据库对象，恕我直言，这并不容易实现可测试的行为。此外，如果您在测试后进行清理，以确保第二个测试正确运行，那么任何此类清理实际上都是第二个测试设置的一部分，而不是第一个测试的拆卸。

使用 DbUnit 的替代方法是在 @Before 设置方法中启动一个新事务，并在 @After 拆卸方法中将其回滚。这取决于您的数据访问层的编写方式。

如果您的数据访问层接受 Connection 对象，那么您的设置例程应该创建它们，并关闭自动提交。此外，还假设您的数据访问层不会调用Connection.commit。假设前面的情况，您可以在拆卸方法中使用 Connection.rollback() 回滚事务。

关于事务控制，下面的代码片段演示了如何使用 JPA 来做到这一点：

@Before
public void setUp() throws Exception
{
    logger.info("Performing the setup of test {}", testName.getMethodName());
    em = emf.createEntityManager();
    // Starts the transaction before every test
    em.getTransaction.begin();
}

@After
public void tearDown() throws Exception
{
    logger.info("Performing the teardown of test {}", testName.getMethodName());
    if (em != null)
    {
        // Rolls back the transaction after every test
        em.getTransaction().rollback();
        em.close();
    }
}

对于其他 ORM 框架甚至您的自定义持久层（如果您已经编写了一个）也必须采取类似的方法。

If you use DbUnit in unit-tests, you can specify that DbUnit should perform a clean-and-insert operation before every test to ensure that the contents of the database are in a valid state before every test. This can be done in a manner similar to the one below:

@Before
public void setUp() throws Exception
{
    logger.info("Performing the setup of test {}", testName.getMethodName());
    IDatabaseConnection connection = null;
    try
    {
        connection = getConnection();
        IDataSet dataSet = getDataSet();
        //The following line cleans up all DbUnit recognized tables and inserts and test data before every test.
        DatabaseOperation.CLEAN_INSERT.execute(connection, dataSet);
    }
    finally
    {
        // Closes the connection as the persistence layer gets it's connection from elsewhere
        connection.close();
    }
}

Note that it is always recommended to perform any setup activities in a @Before setup method, rather than in a @After teardown method. The latter indicates that you are creating new database objects in a method being tested, which IMHO does not exactly lend easily to testable behavior. Besides, if you are cleaning up after a test, to ensure that a second test runs correctly, then any such cleanup is actually a part of the setup of the second test, and not a teardown of the first.

The alternative to using DbUnit is to start a new transaction in your @Before setup method, and to roll it back in the @After teardown method. This would depend on how your data access layer is written.

If your data access layer accepts Connection objects, then your setup routine should create them, and turn off auto-commit. Also, there is an assumption that your data access layer will not invoke Connection.commit. Assuming the previous, you can rollback the transaction using Connection.rollback() in your teardown method.

With respect to transaction control, the below snippet demonstrates how one would do it using JPA for instance:

@Before
public void setUp() throws Exception
{
    logger.info("Performing the setup of test {}", testName.getMethodName());
    em = emf.createEntityManager();
    // Starts the transaction before every test
    em.getTransaction.begin();
}

@After
public void tearDown() throws Exception
{
    logger.info("Performing the teardown of test {}", testName.getMethodName());
    if (em != null)
    {
        // Rolls back the transaction after every test
        em.getTransaction().rollback();
        em.close();
    }
}

Similar approaches would have to be undertaken for other ORM frameworks or even your custom persistence layer, if you have written one.

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