Implement exercise T4L2/sensors-checkout

[jovnc]

Exercise Review

Exercise Discussion

Fixes #144

Checklist

• If you require a new remote repository on the Git-Mastery organization, have you created a request for it?
• Have you written unit tests using repo-smith to validate the exercise grading scheme?
• Have you tested the download script using test-download.sh?
• Have you verified that this exercise does not already exist or is not currently in review?
• Did you introduce a new grading mechanism that should belong to git-autograder?
• Did you introduce a new dependency that should belong to app?

[jovnc]

I'm not sure if its necessary to check reflog that the student performed checkout to the correct commit, as it is almost certain that the student has performed the checkout, else they won't have been able to get the answer.

I have written an alternative implementation with reflog checks, but it seems a little hard to write the repo-smith tests for now (repo-smith supports checkout to specific commit-hash, but there is not way for us to get the commit hash)

def verify(exercise: GitAutograderExercise) -> GitAutograderOutput:
    if not verify_single_checkout(exercise, "Jan 11"):
        raise exercise.wrong_answer(
            [REFLOG_MISSING_TRAVERSAL.format(missing_date="Jan 11")]
        )
    exercise.answers.add_validation(
        QUESTION_ONE,
        NotEmptyRule(),
        HasExactValueRule(CORRECT_ANSWER_Q1, is_case_sensitive=True),
    ).validate()

    if not verify_single_checkout(exercise, "Jan 09"):
        raise exercise.wrong_answer(
            [REFLOG_MISSING_TRAVERSAL.format(missing_date="Jan 09")]
        )    
    exercise.answers.add_validation(
        QUESTION_TWO,
        NotEmptyRule(),
        HasExactValueRule(CORRECT_ANSWER_Q2, is_case_sensitive=True),
    ).validate()

    if not verify_single_checkout(exercise, "Jan 05"):
        raise exercise.wrong_answer(
            [REFLOG_MISSING_TRAVERSAL.format(missing_date="Jan 05")]
        )
    exercise.answers.add_validation(
        QUESTION_THREE,
        NotEmptyRule(),
        HasExactValueRule(CORRECT_ANSWER_Q3, is_case_sensitive=True),
    ).validate()

    return exercise.to_output([SUCCESS_MESSAGE], GitAutograderStatus.SUCCESSFUL)

[jovnc]

For now, this seems to be sufficient, and performing reflog checks can be a possible future enhancement.