Packt has other great resources available so that you can learn about Spring Security and testing. These are as follows:
- Spring Security – Third Edition, by Peter Mularien, Mick Knutson and et al (https://www.packtpub.com/application-development/spring-security-third-edition)
- Mastering Software Testing with JUnit 5, by Boni García (https://www.packtpub.com/web-development/mastering-software-testing-junit-5)