DrupalStandardsListenerTrait is broken

A test-only patch to prove the problem.

The @covers in the [driver]DriverLegacyTest classes

  /**
   * @covers Drupal\Core\Database\Driver\pgsql\Install\Tasks
   */

should just be removed IMHO - they trigger deprecations at the class autoloading time that phpunit-bridge cannot capture, and in any case those are just stub classes, there's no purpose in @covering them. Doing that you can leave the stubbed classes alone.

I can already see people complaining if we remove the docblock. Maybe change to

  /**
   * Tests deprecation of Drupal\Core\Database\Driver\pgsql\Install\Tasks
   */

For the database specific schema test issues, I think it should suffice adding the abstract class Drupal\Core\Database\Schema to the @covers of the abstract class DriverSpecificSchemaTestBase, like

  /**
   * Tests various schema changes' effect on the table's primary key.
   *
   * @param array $initial_primary_key
   *   The initial primary key of the test table.
   * @param array $renamed_primary_key
   *   The primary key of the test table after renaming the test field.
   *
   * @dataProvider providerTestSchemaCreateTablePrimaryKey
   *
   * @covers \Drupal\Core\Database\Schema::addField
   * @covers \Drupal\Core\Database\Schema::changeField
   * @covers \Drupal\Core\Database\Schema::dropField
   * @covers \Drupal\Core\Database\Schema::findPrimaryKeyColumns
   */

and only in case of the test method being overridden at the specific database concrete test class, then specify a @covers for the driver's schema class.

No idea about why the listener test itself throw a deprecation, tho...

... exactly what you did ... :)

Thanks!

Added comments on the MR.

Filed #3350400: Remove DrupalStandardsListenerTrait - it's broken, does not prevent errors, blocks better tooling for an alternative approach.