NodeCreationTest::testFailedPageCreation() should explain exception throwing

API page: https://api.drupal.org/api/drupal/core!modules!node!lib!Drupal!node!Test...

This test expects the node creation to throw an exception, but there's no visible reason why it would do that:

  function testFailedPageCreation() {
    // Create a node.
    $edit = array(
      'uid'      => $this->loggedInUser->id(),
      'name'     => $this->loggedInUser->name,
      'type'     => 'page',
      'langcode' => Language::LANGCODE_NOT_SPECIFIED,
      'title'    => 'testing_transaction_exception',
    );

    try {
      entity_create('node', $edit)->save();
      $this->fail(t('Expected exception has not been thrown.'));
    }
    catch (\Exception $e) {
      $this->pass(t('Expected exception has been thrown.'));
    }

In fact, the magic is in the node title, which a hook in the test module looks out for, and throws an exception if it spots that title.

There really should be a comment somewhere (either on the title array element, or at the try{} statement?) to say that the implementation of hook_foobar() in the test module will cause the exception to be thrown.

Without it, it's hard to understand how the test works, and also could confuse people into thinking there's something inherently wrong about the code used to create a node -- there isn't.