In your code, replace LocalDate.now() with LocalDate.now(clock);. You can then pass Clock.systemDefaultZone() for production and a fixed clock for testing. This is an example : First, inject the Clock. If you are using spring boot just do a : @Bean public Clock clock() { return Clock.systemDefaultZone(); } Second, call LocalDate.now(clock) in your code : @Component … Read more
I strongly recommend that instead of messing with the system clock, you bite the bullet and refactor that legacy code to use a replaceable clock. Ideally that should be done with dependency injection, but even if you used a replaceable singleton you would gain testability. This could almost be automated with search and replace for … Read more
The best strategy is to wrap the current time in an abstraction and inject that abstraction into the consumer. Alternatively, you can also define a time abstraction as an Ambient Context: public abstract class TimeProvider { private static TimeProvider current = DefaultTimeProvider.Instance; public static TimeProvider Current { get { return TimeProvider.current; } set { if … Read more