Make moss page for current course only

[umar221b]

Description

1. Remove usages of undefined a variable in views/courses/moss.html.erb.
2. If the course does not have any assessments, block the moss page with a message and a link to install an assessment.
3. Do not show all courses and their assessments in this page, only the current course and its assessments.

Motivation and Context

Fixes #1861 in addition to making the page for the current course only, which makes more sense as the page is opened within a course's context.

How Has This Been Tested?

Tested locally on the latest docker images.

Here is how the page looks when there is at least 1 assessment:

And here is how it looks when there are no assessments:

I also submitted a few submissions to moss confirm nothing broke there.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

[damianhxy]

What do you think about making the "Add an assessment" button consistent with the "Install assessment" button (from the course home page?)

[umar221b]

What do you think about making the "Add an assessment" button consistent with the "Install assessment" button (from the course home page?)

Yes, that is a good idea. I will do it.

[damianhxy]

Verified that MOSS still works, changes work as expected on course with assessments / no assessments.

Left a few nits, but otherwise lgtm!

[umar221b]

@damianhxy, resolved all the nits, let me know if anything else needs addressing!

[damianhxy]

LGTM. Thanks again for the PR!

[umar221b]

Hi @damianhxy, sorry to go back to this, but I just had a thought that a very usual use case in subsequent runs for a course is to run plagiarism against previous runs of that course. Do you think my work here:

Do not show all courses and their assessments in this page, only the current course and its assessments).

should be reverted?

[damianhxy]

That's also a thought that I had. However, I don't think that's necessary, files from previous iterations can be uploaded via the additional files tar for comparison

[damianhxy]

@umar221b On second thoughts, we had an instructor today request this previous ability to compare across semesters.
Also, it might be tricky to use the additional files tar feature since it doesn't recursively expand archives.

Would it be difficult to revert this change?

[umar221b]

@umar221b On second thoughts, we had an instructor today request this previously ability to compare across semesters. Also, it might be tricky to use the additional files tar feature since it doesn't recursively expand archives.

Would it be difficult to revert this change?

It should not be, let me try to work on something over the weekend.

[damianhxy]

This has been resolved by #2015

[umar221b]

This has been resolved by #2015

Terribly sorry I did not get a chance to work on this.

[damianhxy]

No worries, thank you for all your contributions!