The validation check did not catch errors in `testbase_tutorial_1.py`

[qstokkink]

As found during the testing of #1201, the errors (tracebacks) in the TestCase of testbase_tutorial_1.py were not reported.

It should be determined ASAP whether this is due to unittest.main() not running this particular case or (worse) the entire validation error detection is broken.

In the case of only the single test case being broken, this issue can be scaled back to medium priority.

[qstokkink]

The source of the issue is indeed __name__ not being __main__:

        ...
    raise RuntimeError(__name__)
RuntimeError: doc.basics.testbase_tutorial_1

However, multiple doc files depend on the name being set to __main__. I'll leave this issue as high priority.