correction-helper 2021.11.2

Some helpers to help writing correction bots, use by hackinscience.org.

Correction Helper

Project

This is just a set of tools to help writing correction bots in Python for Python.

It is used for hackinscience, but could be used elsewhere.

Security considerations

Running student code is probably really unsafe, unless you trust your students not to drop you a backdoor.

This projet does not help with security in any ways, maybe take a look at firejail if you have trust issues (Yes you can use correction-helper inside firejail).

Usage

To install it, run: pip install correction-helper.

In your checking code, you can use it like this:

The student_code decorator

This decorator is aimed to catch most problems that could happen in student code, use it simply as:

with student_code():
    their_function()

Find a more complete example in the examples/ directory.

Allowed parameters for student_code, and their default values

exception_prefix="Got an exception:"

Printed right before the exception, if any.

friendly=False

To use, or not friendly-traceback instead of bare Python exceptions.

print_allowed=False

To allow the use to print to stdout / stderr, you can read what they printed using the value of the context manager:

with student_code(print_allowed=True) as run:
    their_function()
assert run.stderr == ""
assert run.stdout == "42"

print_allowed can be set to None meaning "neither allowed nor really denied": the student output will be printed along with the print_prefix, but it's not considered a failure.

print_prefix="Your code printed something (it should **not**):"

Message to display when they printed and print_allowed was False.

Good practices

Try first if the student code works, if it works, it works. Only if the code does not work, try to understand why.