Question

我正在尝试创建一个数据库连接库，以便在我的所有应用中使用。我想确保这个库完全经过单元测试，因此我尝试使用依赖注入。

我有这个课我想确保测试：

public class ConnectionFactory {

    private String dataSourceName;

    public ConnectionFactory(String dataSourceName) {

        if(dataSourceName == null) {
            throw new NullPointerException("dataSourceName can't be null");
        }

        this.dataSourceName = dataSourceName;
    }

    public Connection getConnection() throws SQLException {

        Connection connection = getDataSource(dataSourceName).getConnection();

        if(connection != null) {
            return connection;
        }       

        ...
    }

    // Get a datasource object
    private DataSource getDataSource(String dataSourceName) {
        ...
        try {
            Context ctx = new InitialContext();
            dataSource = (DataSource) ctx.lookup("java:comp/env/" + dataSourceName);
        } catch (NamingException e) {
            ...
        }

        return dataSource;
    }

}

我希望能够通过简单的方式从我的所有应用程序中调用此类：

public class MyApp {
    public static void main(string[] args) {
        ConnectionFactory connectionFactory = new ConnectionFactory("jdbc/myDataSource");
        Connection connection = connectionFactory.getConnection();
    }
}

我已经开始为这个ConnectionFactory编写单元测试，但很快就意识到，使用我当前的代码，我无法模拟DataSource对象，因此它试图实际连接到真正的数据源。

@RunWith(Nested.class)
public class ConnectionFactoryTest {

    public class Constructor {

        @Test
        public void shouldThrowNullPointerIfParamIsNull() {
            assertThatExceptionOfType(NullPointerException.class)
                .isThrownBy(() -> { new ConnectionFactory(null); })
                .withMessage("dataSourceName can't be null");
        }
    }

    public class GetConnection {

        public class WithDataSourceAvailable {

            @Test
            public void shouldErrorIfParamIsNull() {
                ConnectionFactory connectionFactory = new ConnectionFactory("jdbc/myDataSource"); // <-- This is going to fail b/c it's trying to actually fetch a real data source
            }
        }   
    }
}

如何正确使用依赖注入，以便我可以编写实际上并未尝试连接数据源的单元测试？

Answer 1

看看Mockito我觉得这种模拟很容易使用。

尝试用示例理解Java依赖注入

1 个答案: