Layout builder block for extra fields should appear in "Content Fields" category and not "Content"

Fix looks good, NW for tests

Test added -- verifies that an extra field exists within the "Content fields" category.

1. +++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php
   @@ -688,13 +688,28 @@ public function testLayoutBuilderChooseBlocksAlter() {
   +        if ($summary->getText() == "Content fields") {
   

   == => ===
   Use single quotes.

2. +++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php
   @@ -688,13 +688,28 @@ public function testLayoutBuilderChooseBlocksAlter() {
   +          $this->assertTrue($extra_field !== FALSE, 'Content field contains extra label');
   

   We should omit the message.

+++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php
@@ -688,13 +688,28 @@ public function testLayoutBuilderChooseBlocksAlter() {
+    foreach ($page->findAll('css', 'details.js-layout-builder-category') as $category) {
+        $summary = $category->find('css', 'summary');

Instead of iterating each details element, we could just grab the details element with summary = 'Content fields' by xPath, and assert it contains Extra label.

Good call on making the test more efficient by targeting via xpath, rather than iterating. All suggested changes are addressed here.

Can you post a version of the patch with just the test changes, to prove they catch the bug? Also include the full patch in the same comment so the testbot doesn't get confused

Good call, Tim. Patch added with only the test changes.

+++ b/core/modules/layout_builder/tests/src/Functional/LayoutBuilderTest.php
@@ -688,13 +688,24 @@ public function testLayoutBuilderChooseBlocksAlter() {
+    $this->clickLink('Add Block');

It's Add block now. Let's get another pair of patches. And if you upload the failing one first, the issue will stay at Needs Review instead of marking it back to Needs Work

Understood!

Looks good to me, thanks!

Committed 63148fa and pushed to 8.8.x. Thanks!