[List Ops]: Potential mismatch between instructions and tests

[OndrejMarsalek]

The instructions for append say "given two lists, add all items in the second list to the end of the first list". Although I understand someone could read it the other way, to me, a strict reading of this is that the first list should be modified. The tests do not guard against constructing a third list that contains items from both inputs, and people will commonly solve this with return list1 + list2. I think that either the instructions or tests should be updated, but I am not submitting a PR, as it is not clear to me what the original intention was.

[github-actions]

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[BethanyG]

Hi @OndrejMarsalek 👋🏽

Thanks for filing this issue.

A few things here:

1. Usually, tests only check outcomes, and do not check implementation. So checking that the first list was modified vs a new list returned is stretching that definition a little bit. However, the instructions do mention explicitly that list modification is expected, so....
2. Per my comments in issue [List Ops]: def concat(lists) possible test error #3142, the exercise descriptions and test data for this exercise are pulled from problem specifications, so I'd suggest opening up an issue there to discuss the intent of the exercise task, and weather or not it is valid to create a new list, or if we should be explicitly checking for modification of the first list. I suspect this varies quite a bit from language to language, since some are pass by reference and some are pass by value.... and some (Python) are pass by object reference.
3. We could potentially create a Python-only test case that does explicitly check for modification, but I think I'd like to have a discussion in problem specifications first.

[BethanyG]

Closing to track under #3156. Please give a shout if you'd like to work on the issue.