baeldung
https://www.baeldung.com/spring-boot-testing
    !!!
https://www.baeldung.com/spring-boot-testing-pitfalls
https://www.baeldung.com/integration-testing-in-spring

2021
https://reflectoring.io/spring-boot-test/
    https://github.com/thombergs/code-examples/tree/master/spring-boot/spring-boot-testing
https://reflectoring.io/spring-boot-web-controller-test/
2019
https://reflectoring.io/spring-boot-data-jpa-test/
https://reflectoring.io/unit-testing-spring-boot/
https://habr.com/ru/post/446184/
2018
https://habr.com/post/431306/
https://dzone.com/articles/unit-and-integration-tests-in-spring-boot-2
https://reflectoring.io/testing-verticals-and-layers-spring-boot/
2017
http://www.springboottutorial.com/integration-testing-for-spring-boot-rest-services
2016:
https://moelholm.com/2016/10/22/spring-boot-separating-tests/
2015:
http://www.frommknecht.net/spring-spock-docker-integration/