Add sorts to our collection tests that are inspecting values in the collection, to not be dependent on per-DB default order

I also have this problem locally w/ `UserTest` because I have MySQL 8 running.

That means we'd run into this problem in the future even without Postgres. Core is keeping us honest :)

It could be viewed as a feature because responses will be uniformly sorted across different databases.

+1

I think the risk of actually breaking assumptions is pretty low. _Maybe_ some hardcoded tests that people have will break, but the solution is simple: fix the test's order/add a sort to the request

+1

#1 incurs into a performance penalty, so -1 for me. I like #3 over others.

Could be bad because we'll never test the "not sorted" case

Tests assert that sorting works. Unsorted defaults to DB implementation (not on us to test). We only need to test that an unsorted collection works. That could be a dedicated test.

#1 incurs into a performance penalty, so -1 for me.

I hadn't thought about that. This is an excellent point. 👏 🙏

@e0ipso convinced me we want #2 or #3.

So the patch is green for #3. @e0ipso expressed his preference for this approach. Great!

I have just one concern: we're now coupling many of our tests to sorting. On the one hand this is completely reasonable, on the other hand it means there is a very slight risk in that we're no longer testing the absence of sorts. However …

+++ b/tests/src/Functional/ResourceTestBase.php
@@ -1038,6 +1038,20 @@ abstract class ResourceTestBase extends BrowserTestBase {
+    // This asserts that collections will work without a sort, added by default
+    // below, without actually asserting the content of the response.
...
+    $response = $this->request('HEAD', $collection_url, $request_options);
...
+    // Different databases have different sort orders, so a sort is required so
+    // test expectations do not need to vary per database.
+    $default_sort = ['sort' => 'drupal_internal__' . $this->entity->getEntityType()->getKey('id')];
+    $collection_url->setOption('query', $default_sort);

Gabe already thought about that :)

Given that, I'm RTBC'ing this, but not yet committing: I'd like @e0ipso to explicitly +1 this too.

+1

🎉