[Admin] Store Credit Reasons edit/update & New request specs to appease Codecov

[MadelineCollier]

This PR finishes off this issue but it doesn't have an issue ID yet as the issue is still in draft and there is (still) a GitHub bug preventing opening the issue.

This PR migrates the editing/updating of existing store credit reasons to the new admin interface, following the existing pattern used for tax categories.

The form is rendered via a modal dialog on the store credit reasons list by leveraging Turbo frames. Successful updating leads to a turbo stream page refresh, which updates the existing list preserving the query params and the scroll position, for a consistent UX.

The second part of this PR is adding new request specs to appease codecov, which was not happy with the coverage provided solely by our feature specs. I will add similar request specs for all the past PRs I have put up if/when this change has proven to increase the coverage percentage.

The attached video shows the functionality visually:

Screen.Recording.2024-08-13.at.4.20.47.PM.mov

Summary

Checklist

Check out our PR guidelines for more details.

The following are mandatory for all PRs:

• I have written a thorough PR description.
• I have kept my commits small and atomic.
• I have used clear, explanatory commit messages.

The following are not always needed:

• 📖 I have updated the README to account for my changes.
• 📑 I have documented new code with YARD.
• 🛣️ I have opened a PR to update the guides.
• ✅ I have added automated tests to cover my changes.
• 📸 I have attached screenshots to demo visual changes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.79%. Comparing base (d99aaf2) to head (24a9259).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5821      +/-   ##
==========================================
+ Coverage   88.76%   88.79%   +0.02%     
==========================================
  Files         736      737       +1     
  Lines       17201    17227      +26     
==========================================
+ Hits        15269    15296      +27     
+ Misses       1932     1931       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[MadelineCollier]

Nice, it looks like codecov is happy at last.

It seems like the only thing not covered by these new specs is this one private method:

 # admin/app/controllers/solidus_admin/store_credit_reasons_controller.rb

    private
    def load_store_credit_reason
      @store_credit_reason = Spree::StoreCreditReason.find_by!(id: params[:id])
      authorize! action_name, @store_credit_reason
    end

I actually don't see being called anywhere. @rainerdema @elia This looks like it's a common pattern in the new admin controllers, do you know what these load methods are (/were?) being used for?

[elia]

I actually don't see being called anywhere. @rainerdema @elia This looks like it's a common pattern in the new admin controllers, do you know what these load methods are (/were?) being used for?

@MadelineCollier I think you can remove it, must be a leftover from a copy/paste.