Unable to change Custom Block view mode

Sounds like we're missing some tests here

This should fix it - not tests yet, not sure if I can get to it by next week, so someone else can take over freely

I did the patch adding a test view mode and selecting the value to then determine if selected.
The first one is the test and the second test+ patch.

+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
@@ -58,6 +70,14 @@ public function testCustomBlockCreation() {
+    $this->drupalGet('admin/structure/block/manage/stark.testblock');

I think these ids have changed now, will re-test - otherwise rtbc

#3: custom_block_view_mode-2099417-3.patch queued for re-testing.

Patch + test again with id modification

1. +++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
   @@ -46,9 +46,21 @@ protected function setUp() {
   +    // Add a new 'View Mode' and verify if it is seleted as expected.
   

   Typo: 'seleted'

2. +++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
   @@ -46,9 +46,21 @@ protected function setUp() {
   +    // Add a new 'View Mode' and verify if it is seleted as expected.
   

   No need to wrap 'View mode' between quotes, just write 'Add a new view mode ...'

3. +++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
   @@ -58,6 +70,14 @@ public function testCustomBlockCreation() {
   +    // Change the 'View Mode'.
   

   Same here

Fixed #8 point 2.

Great, thanks!

Committed/pushed to 8.x, thanks!