Overview

The CPS-RI module which is responsible for data persistence and retrieval from the database is based on
Spring Data framework. Following components are used:

Persistence service implementations (logic layer) → these are defined as Java classes
JPA repositories (data access layer) → these are defined as Java interfaces, corresponding objects
are created by Spring framework at runtime

In order to reach the desirable level of reliability it's expected the functionality to be covered with tests.

While using unit tests is a common approach for Java application testing, it seems insufficient in a context of testing the
actual data persistence/retrieval functionality:

Test covers a small slice of functionality while the major piece served by external services (Spring data framework,
JDBC driver and database itself) remain not used (not tested)
JPA repositories can be only used as mocks to test the service implementation but JPA repositories are not subject
for tests themselves because of definition as interfaces
The effort to setup the expected behaviors for JPA repository mocks is comparable with (or exceeds) the effort
required to setup the actual data for same cases;

From other hand the benefits of using integration tests with real database instance are following:

All levels of abstraction are involved in tests, it means all of them are impacting on test results same way as within
a deployed application
JPA repositories are subjects of test
Complete validation of expected behavior, including database schema initialization
Can be used on build, keeping desired level of reliability and consistency
Tests can be used on development stage making the database deployment (on dev environment) optional

Overview

Components

Test Containers

Test container life circle management

@SpringBootTest

Test template

Resources

CPS Persistence layer testing

Overview

Components

Test Containers

Test container life circle management

@SpringBootTest

Test template

Resources