如何在没有ORM的情况下对DAO进行单元测试

Question

I am writing a JAX-RS web service right now. My database logic has been compartmentalized into DAO interfaces (eg interface ItemDAO and concrete implementation class JDBCItemDAO ), which are injected into my controllers via Dependency Injection. Right now, it is relatively simple to unit test my controllers by giving them mock DAOs. However, I can not really test my DAOs because they use the JDBC API, and don't have any dependencies, other than a ConnectionFactory (returns java.sql.Connection to callers). I can't really just pass a mock Connection to the DAO because just verifying the SQL query that was in the DAO isn't enough. I want to be able to test that it works in the database. How can I achieve this?

Answer 1

1. Set up a database. If you write standard SQL without depending on database-specific features you can use an in-memory database like H2 .
2. Set up DataSource object pointing to your database. This is preferable to ConnectionFactory you have right now in DAOs. You don't want to establish new physical connections all the time as this is expensive.
3. Use a pooled DataSource in your production code eg HikariCP and maybe use something simplier in your test code eg SingleConnectionDataSource