Debugger doesn't trace into doctests

[pdawyndt]

The debugger doesn't run doctests, probably because it's instructed not to trace into modules (like testmod). Would however be highly relevant if student code were still traced while running the doctests. Of course we do not want to trace running the functionality of the `testmod' module itself.

[pdawyndt]

FYI: Here's a nice example of a solution where the original Python Tutor heavily suffers while rendering some frames with many objects/references, whereas the new implementation runs much more smoothly. As an additional advantage: the bug in this code can't be found in the Python Tutor due to the 1000-frame limit, where the new implementation is helpful because that limit is removed.

This sample code also has a doctest that could not be debugged as such: I had to inline the doctest as part of the code itself before I could start debugging.

[pdawyndt]

Example for testing purposes:

def echo(arg):

    """
    >>> echo(42)
    42
    >>> echo('spam')
    42
    >>> echo([1, 2, 3, 4])
    [1, 2, 3]
    """
    
    return arg

import doctest
print(doctest.testmod())

Papyros does not call the echo function at all (should have called it three times), so the testmod function does not discover the testcases in the doctest. The output indicates that the testmod function itself did execute.

[bmesuere]

We never trace into external libraries. The performance cost is too high.

[pdawyndt]

We never trace into external libraries. The performance cost is too high.

But this is a special case, where the trace leaves the submitted code for `doctest.testmod(), which reroutes execution back to eval/exec part of the submitted code.