如何调试代码和可视化执行

Question

I'm taking open-source class. I am given doctests and a CLI to test my code and see if it passes, however, how can I visualize my code to see what is happening? For instance, I am having a hard time understanding how the for loop is working and I would like to see what list is assigned in each recursion.

The file has many functions so running -m doctest isn't ideal and also doesn't show the execution. When I run debug mode in vs code and set a breakpoint at the function, it never steps into the function. I imagine this is because in the file I never call nut_finder() but I don't want to start adding to the source code since that would defeat the purpose of the doctest. I can also run python interactively but that too won't show me how the code is executing.

The only solution I have found is to use a tool that visualizes the code, however, this requires me to manually copy and paste stuff. This also will become a problem from large applications and multi-file applications. So in short, how can I learn the right way to debug my code.

# lab05.py
def nut_finder(t):
"""Returns True if t contains a node with the value 'nut' and
False otherwise.

>>> scrat = tree('nut')
>>> nut_finder(scrat)
True
>>> sproul = tree('roots', [tree('branch1', [tree('leaf'), tree('nut')]), tree('branch2')])
>>> nut_finder(sproul)
True
>>> numbers = tree(1, [tree(2), tree(3, [tree(4), tree(5)]), tree(6, [tree(7)])])
>>> nut_finder(numbers)
False
>>> t = tree(1, [tree('nut',[tree('not nut')])])
>>> nut_finder(t)
True
"""
if label(t) == 'nut':
    return True
for b in branches(t):
    if nut_finder(b):
        return True
return False

Answer 1

I think python 3.7 and up: type breakpoint() right where you want it to stop. It is a shortcut for using pdb module ( https://docs.python.org/3/library/pdb.html ).