如何在两个测试类之间共享外部资源？

Question

我正在努力理解使用ExternalResource的好处。文档和其他帖子（Junit@Rule是如何工作的？）所有这些都暗指能够在类内的测试之间共享代码和/或在测试类之间共享代码。

在功能/集成测试中，我试图使用ExternalResource进行DB连接，但我不知道如何跨类共享该连接。事实上，在这种情况下，我并没有看到比@Before/@After有什么好处。我是不是用错了，还是我遗漏了什么？

public class some_IntegrationTest {

    private static String id;
    Connection connection = null;

    //...

    @Rule
    public ExternalResource DBConnectionResource = new ExternalResource() {
        @Override
        protected void before() throws SQLException {
            connection = DbUtil.openConnection();
        }

        @Override
        protected void after() {
            DbUtil.closeConnection(connection);
        }
    };

    @BeforeClass
    public static void setUpClass() throws SQLException {
        System.out.println("@BeforeClass setUpClass");
        cleanup(id);
    }

    //I want to do something like this
    @Test
    public void test01() {
        cleanupData(connection, id);
        // do stuff...
    }

    @Test
    public void test02() {
        cleanupTnxLog(connection, id);
        // do stuff...
    }

    //...


    private static void cleanup(String id) throws SQLException {
        LOGGER.info("Cleaning up records");
        Connection connection = null;
        try {
            connection = DbUtil.openConnection();
            cleanupData(connection, id);
            cleanupTnxLog(connection, id);
        } finally {
            DbUtil.closeConnection(connection);
        }
    }

    private static void cleanupData(Connection connection, String id)
        throws SQLException {
        dao1.delete(connection, id);
    }

    private static void cleanupTnxLog(Connection connection, String id)
        throws SQLException {
        dao2.delete(connection, id);
    }
}

Answer 1

我会这样做：

public class DbConnectionRessource extends ExternalRessource {

    private Connection connection;

    @Override
    protected void before() throws SQLException {
        connection = DbUtil.openConnection();
    }

    @Override
    protected void after() {
        DbUtil.closeConnection(connection);
    }

    public Connection getConnection() {
        return connection;
    }
}

然后在测试中使用它，如下所示：

public class SomeIntegrationTest {
    @Rule
    public DbConnectionRessource dbConnectionResource = new DbConnectionRessource();

    // ...

    @Test
    public void test01() {
        cleanupData(dbConnectionResource.getConnection(), id);
        // do stuff...
    }

    // ...
}

[未经测试]