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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; the implementation but JPA repositories are not subject
  for tests themselves because of definition as interfaces
• The effort to setup the expected behaviors
  for expected behaviors for JPA repository mocks is comparable with (or exceeds) the effort
  required to setup the actual data for same cases;
  but JPA repositories are not subject for unit tests

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

Components

Test Containers

Test container life circle management

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