Disallow <div>, only allow <drupal-entity>

Turns out I can't fix this due to a bug elsewhere — see #2547085-12: Remove the <drupal-entity>/<div> placeholder instead of embedding the entity as a child:

I ran into this bug in yet another way: via the test coverage while working on #2628358: Disallow <div>, only allow <drupal-entity>:

// Test that tag of container element is not replaced when it's not
    // 'drupal-entity'.
    $content = '<not-drupal-entity data-entity-type="node" data-entity-id="' . $this->node->id() . '" data-view-mode="teaser">this placeholder should not be rendered.</not-drupal-entity>';
    $settings = array();
    $settings['type'] = 'page';
    $settings['title'] = 'test entity embed with entity-id and view-mode';
    $settings['body'] = array(array('value' => $content,

It says "test that anything else than is NOT replaced" … but then it tests that it DOES get replaced! Yet it also tests that </not-drupal-entity> still exists… And both tests pass! That is not logically possible!

Except this bug makes it possible: because we never ever replace the original DOM node, we also cannot reliably test some cases, because the original HTML is never actually replaced.

This is therefore postponed on that issue.

Turns out I can't fix even that due to a bug further down — see #2547085-16: Remove the <drupal-entity>/<div> placeholder instead of embedding the entity as a child:

But… HAH! That won't actually work, because embed's replaceNodeContent() is broken: see #2602316: Allow any HTML as content for replaceNodeContent. It will only actually import the first DOM node. And the first DOM node when rendering an article template happens to be… a text DOM node with a newline in it. The second DOM node is the <article class="type-node" …> HTML that we expect.

So, with the above, tests actually fail for both patches because embed is broken…

Now working on #2602316: Allow any HTML as content for replaceNodeContent.

And the other patch was also committed. Yay :)

Patch forthcoming.

And patch.

CR at https://www.drupal.org/node/2628748.

Fix one of the related issues: I accidentally referenced this issue, which is nonsensical of course.

#8: Done: https://www.drupal.org/node/2628748/revisions/view/9172988/9173534.

Published the CR.

And yay, one child issue of #2628168: Clean up Entity Embed's data model completed!