Question

I am trying to write a unit test for a DAO implemented using MyBatis using annotations. I would like to instantiate that DAO to unit test against my (in-memory) database. However, the only way I see to instantiate it is through a SqlSessionFactory and the only way I see to see instantiate one of those is by using a SqlSessionFactoryBuilder only of whose methods that a configuration file.

However, in my unit test I already have a connection to the in-memory database can I just use that to somehow instantiate the mapper? That would also allow me to mock or spy the Connection later if I needed to for a test.

Answer 1

The SqlSessionFactory class has a openSession(Connection connection) method. You can use it to retrieve a SqlSession using the Connection you have to your in memory db.

You can build a SqlSessionFactory programmatically without using a configuration file with the following code:

Environment environment = new Environment("ID", transactionFactory, dataSource);
Configuration configuration = new Configuration(environment);
configuration.addMappers(mappersPackageName);
// Other configuration tweaks
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(configuration);

Then you can mock or stub the DataSource to return your desired Connection instance.