Using EmbeddedPostgres to test Spring Data JPA repositories

[slwcz]

Hi,
I am developing an application which uses Spring Data JPA and Postgres DB. Now when writing integration tests, I am struggling how to properly implement the test because I am always hitting the real database and not the embedded one.
Under src/main/resources/META-INF I have persistence.xml referring to the real database. I am using RESOURCE_LOCAL because it is a standalone application. Therefore I dont have any datasource declared.
When the initialization of my integration test happens, JPA repository is auto-discovered, LocalEntityManagerFactoryBean initialized which boils down to reading the ersistence.xml and initializing the connection to the real DB. I also see in the log of the integration test, that embedded Postgres is initialized but in fact "the JPA repository under test" queries the real DB which is not intended.
My question is:

• is my scenario supported?
• how can I bypass the persistence.xml parsing and initialization provided that there is no datasource in my Spring context. Can I duplicate persistence.xml to src/test/resources? How would the JDBC URL pointing at the embedded Postgres look like?

Thank you.
Slavek

[tomix26]

Hey Slavek, thanks for the question. The Zonky library is quite flexible and supports many scenarios, including integration with Spring Data JPA. When using standard Spring Boot auto-configurations, everything should work out-of-the-box. However, if you're using a custom configuration, certain manual steps may be necessary, which is probably your case.

The Zonky library needs a data source bean to replace in order to work properly. So if you have a data source defined in persistence.xml, you need to extract it as a Spring bean.

If you cannot extract the data source from persistence.xml (for example, because it's a JNDI resource), the situation becomes more complex. In such a case, the best approach is probably to have dual configurations - one for the application and another for tests. And use a test Spring profile to activate or deactivate the test configuration. More information here: https://docs.spring.io/spring-framework/reference/testing/annotations/integration-spring/annotation-activeprofiles.html