In a lot of projects I have been on I’ve seen the following approaches when it comes to application logging in test:

1. The most popular option: It is completely ignored, either by pumping it into a mock or a NullLogger
2. It is tested by verifying that the correct log messages are written. This is usually done to satisfy a ‘strict’ mocking framework.

Neither of these options are ideal in my opinion. The first option totally hides the logging, making it hard to see if it is actually valuable. The second option adds too much noise into the tests, since verifying that the message is written doesn’t tell me much.