Add user access checks to 'more' link

The Issue Summary has steps to reproduce for Drupal 8. Is this still valid? Let's get an issue summary update, including a proposed resolution, and a set of the latest screenshots. And let's put the steps to reproduce under the correct heading. Adding tag for an issue summary update.

I took a very brief view of the patch.

1. +++ b/core/modules/views/tests/src/Functional/Plugin/DisplayTest.php
   @@ -294,6 +294,13 @@ public function testReadMoreCustomURL() {
   +    // Test if user doesn't have permission to link read more doesn't display.
   

   This sentence does not make sense to me. For one there are two negatives. And there should be quotes around 'read more'.

2. +++ b/core/modules/views/tests/src/Functional/Plugin/DisplayTest.php
   @@ -294,6 +294,13 @@ public function testReadMoreCustomURL() {
   +    $this->assertStringNotContainsString('/admin/content', $output, 'The read more link with href "/admin/content" was not found.');
   

   This is testing the absence of something. Do we have a test for the presence of 'read more' link when it should be visible?

3. +++ b/core/modules/views/src/Plugin/views/display/DisplayPluginBase.php
   @@ -2115,12 +2115,26 @@ public function renderMoreLink() {
   +      // Add cache metadata with the link target page.
   

   I keep reading reading this sentence and expect a final prepositional phrase, as in, "Add cache metadata with the link target page to ....". Can this be clearer?

#34.1 updated
#34.2 a few lines above it's testing for the link
#34.3 updated

Updated issue summary.

Patch #35 applied successfully and working as expected.

Rolled a new solution into an MR with the test coverage from #35

Re #37.3 this test case is specifically testing the output of the read more link, nothing more. There's plenty of other assertions there to ensure it's working in other scenarios and there's nothing else in the output to add a positive assertion to.

Worked on this as part of node issue triage before realising this is not node related at all

LGTM