(*testing.T).Log doesn’t actually print out logged messages unless a test fails. Calls to Log are cached and then after the test completes, the testing package checks if it failed or succeeded. If it failed, all log events are printed with the hope that it’ll help the user identify the problem. If it succeeds, then there’s no reason to print the logs.
If you want to force the log messages to print, then add this to your user settings JSON file in VS code: