JUNIT

https://www.javaguides.net/2018/07/junit-4-annotations-with-examples.html

https://www.javaguides.net/2018/07/junit-5-assertions-with-examples.html

https://www.javaguides.net/2018/07/junit-4-aggregating-tests-in-suites.html

https://www.vogella.com/tutorials/Mockito/article.html

https://dzone.com/articles/a-guide-to-mocking-with-mockito

https://www.javaguides.net/2018/09/spring-boot-2-rest-apis-integration-testing.html