Replace Console.WriteLine in NUnit

You can see the console output. You just have to select the "Text Output" tab in the NUnit GUI runner.

If you are using the ReSharper test runner, the console output should be displayed. Ensure that the test runner output window is displayed by clicking the "Show Output" button in the test runner tool bar:

You should then get something as follows:

In NUnit v3, you can also write to the test results output for debugging with

TestContext.Out.WriteLine("Message to write to log");

Try using System.Diagnostics.Debug.WriteLine instead.