Generic Index Page

[kacperpONS]

What is the context of this PR?

Note that the Front End will differ from the current About us page that's given on the Jira card as an example of an Index page; that includes but isn't limited to the fact that the list is displayed vertically.
I've talked to Helen and John D and it appears that the design for the Index page hasn't been finalised yet, so it's likely it'll have to be revisited.

Because there's no design to refer to and the Jira card doesn't specify that, I've decided give the publisher the flexibility to add Featured pages with or without the description field.
That might cause some formatting issues when some of the block will and some won't have the description.
In order to prevent that the backend might have to be modified to get rid of this problem by making the description mandatory, making the size of the Featured items consistent.

Similarly, when child pages are displayed as the Featured items, they'll currently be displayed without the description field. Depending on the design, this might have to be changed for example by allowing the publisher to add a description for the child pages or automatically pull information from the child page summary.

How to review

Command to the unit tests just for this page:

poetry run coverage run ./manage.py test --parallel --settings=cms.settings.test cms.standard_pages.tests.test_models --keepdb

1. For Functional testing, make sure that the new "Featured items" functionality works:

   • Check that if no "Featured items" are selected, the children pages of the Index page are displayed,
   • Check that if at least one "Featured item" is selected, then it's displayed correctly

2. The page also uses the RelatedContentBlock in a new context - so far it was only used as one of the StreamFields available in the main content of pages. Here - it's used on it's own and as rendered as a separate onsRelatedContent component the Design System. Worth double checking that it renders correctly :)

Jira card

https://jira.ons.gov.uk/browse/CMS-180

[kacperpONS]

Just a note - the linters just made me format the automatically generated migrations file, might be a sign our linters are a tad too restrictive...

[kacperpONS]

Note regarding the above commit:

The check added is meant to prevent the situation where:

1. We add and save a page that is meant to be a Feature item on the Index page (but not publish it)
2. The page is selected as a featured_item in the RelatedContentBlock (which allows both published and not published pages to be selected)
3. When trying to access the page details via LinkBlockStructValue.link returns None (because it checks that the page is live and ignores it if it isn’t)
4. We get an error in the preview because we try to access the dictionary returned by .link, with
   featured_item.value.link["text"]
   but it’s None.

Possibly that’s not the most elegant solution so I’m open to suggestions.

PS It appears that doing trying to access the .link dict with getatt([featured_item.value.link], “text”, ””)
sends the empty string to the Document list UI component, and it’s still being rendered in the preview without any text in it.

PPS Shout out to @nehakerung for spotting that!

[nehakerung]

I think the altered migrations need to be addressed before this merges to main.

[sanjeevz3009]

Left a few minor non-blocking comments around clean code/ refactoring. Tested everything locally, and everything seems to be working well. Looks good to me!

Great work ;)

[nehakerung]

LGTM - had a check through and think it looks great.

[sanjeevz3009]

LGTM!