At the end of tutorial, "Add a test", the tutorial leaves the code in a broken state. The next tutorial "Compile and install the application", assumes that the code is fully functional.

I recommend that the fix be done in the "Add a test" tutorial, so that the user is left with a working example, as that is where the code was initially broken. Otherwise, if the fix is done in Compile and install the application, the text would have to deal with the developer who goes directly to that tutorial, without going through the previous tutorials.

If the fix is done in "Add a test" tutorial, you just need to add a paragraph that has the developer edit the broken file, by un-commenting the working code, and deleting the broken code.