FIX / DOC Add support ElementalArea in DataObject

[sabina-talipova]

Description

Create new section in docs directory with example how to use ElementalArea together with DataObject.

Changes

New condition was added in CMSEditLink() in BaseElement class for cause when $page is not an instance of SiteTree and Element is not inline editable. Also new condition for checking of existing the CMSEditLink() method in class that has relation with ElemantalArea.

Parent Issue

• Elemental Area can't easily be added to a non-Page DataObject and edited in a ModelAdmin #871

[emteknetnz]

I wasted able to get the CMS preview to work. Using the debugger, cmsPreview() nor PreviewLink were getting called. I followed the instructions inthe document I'll paste my code below.

[emteknetnz]

Also could you rename using_elementalArea_with_dataObject.md to be lower case using_elementalarea_with_dataobject.md - you'll probably need to follow these instructions

[emteknetnz]

Seems like these docs are duplication of what's already on framework - https://docs.silverstripe.org/en/4/developer_guides/customising_the_admin_interface/preview/ / https://github.com/silverstripe/silverstripe-framework/blob/4/docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/04_Preview.md

We should aim to not have duplicated docs if possible - would it be possible to just remove the duplicated bits and link to the framework docs?

[emteknetnz]

Seems a lot better now that the Previewable examples have been removed.

I've followed the example code locally, the BlogPost's aren't publishable, which is unexpected given the content blocks are inline publishable

[GuySartorelli]

I haven't actually tried running the example locally yet, but I figured I may as well submit this much of the review while I do that.

There are some questions here that you may have already gone through with Steve - if so, sorry about the duplication. Just want to make sure I fully understand what is happening here.

[GuySartorelli]

Nice work!
There are a few minor tweaks to make on the documentation, and some code quality tweaks to make, but I think it's just about ready.
I haven't done so in my review, but once you've made these changes can you please make sure to run phpcs? (You probably already do this but just in case)

At some stage we'll want behat coverage to ensure elemental blocks continue to work in arbitrary DataObjects in the future... I'll let you decide whether you want to do that with this PR or create an issue for it to be added later, given the time you've already spent on this one.

After thinking about this I'm taking this decision for you :p just creat an issue, it should be a separate piece of work. Adding behat tests for this will be a big piece of work.

[sabina-talipova]

Regarding "After thinking about this I'm taking this decision for you :p just creat an issue, it should be a separate piece of work. Adding behat tests for this will be a big piece of work."
I think, it would be better to implement behat tests together with this task, then leave it for long time. Probably, test cases for Elements on a Page already exist, I just need to add tests for DataObject. Am I right?

I also want to add test cases for canDelete, Link and AbsoluteLink methods.

[GuySartorelli]

I just need to add tests for DataObject. Am I right?

You'd also need to add fixtures for it, which can't be done easily as TestOnly objects in behat, so it would mean adding new fixtures to https://github.com/silverstripe/silverstripe-frameworktest and adding that repository as a dev dependency for elemental.
I won't stop you from adding that to this PR if that's what you'd prefer to do, but if you get frustrated with it I'd also be okay merging this without behat tests.

I also want to add test cases for canDelete, Link and AbsoluteLink methods.

That sounds like a good idea

[GuySartorelli]

Tests are failing. Ignore the code coverage one for now - there's not really anything you can do about that. I'm hoping it will resolve itself by the time you push a fix for the other failing tests.

[GuySartorelli]

There's a note above to address, plus some changes requested in silverstripe/silverstripe-frameworktest#105 - once those are addressed I'll test the behat tests locally

[GuySartorelli]

Sorry, should have noticed this in the last review.
Looks good now, I'll check that the behat tests run with the fixtures in frameworktest when I have a moment. If that passes fine, I'll approve the fixtures and then get travis to run the tests again here before merging.

[GuySartorelli]

Behat tests work locally. Restarting travis tests now that the fixtures are merged.

[GuySartorelli]

Tests are failing that aren't failing on the 4.8 branch

[GuySartorelli]

Tested locally, works as expected.
The only remaining failures are also observed on the 4.8 branch, and are unrelated to this PR.