Making Time-dependent Features Testable

As professional developers, we are all striving to provide 100% automated test coverage for all code we write. However, one particular class of features is quite difficult to test - those that depend on current time, in one way or another. For example, an expiring token - how we test that it actually expires in 20 minutes? In this article, I share a simple technique that helps with this challenge, that I have been personally using for quite some time. As an extra bonus, I will also share the 'simplest' stopwatch utility methods.