mockito

1. https://medium.com/@gustavo.ponce.ch/spring-boot-restful-junit-mockito-hamcrest-eclemma-5add7f725d4e 
2. can we use same mock in two different test methods? what would be its implications ie. pros and cons?
3. what layer is best suitable for being tested through mockito? controller or service? or both?
4. https://dzone.com/articles/spring-boot-unit-testing-and-mocking-with-mockito
5. @Mock vs @InjectMocks?
6.