Call to an undefined static method PHPUnit\Util\ErrorHandler::handleError() in DrupalStandardsListenerTrait

This was first introduced in #2933991: Deprecation tests fail when all PHPUnit tests are run via PHPUnit but it looks like the PHPUnit ErrorHandler was refactored in PHPUnit 8.3 and handleError() was removed: https://github.com/sebastianbergmann/phpunit/commit/db1dce395c1843f09531...

What happens if we don't change the error handler at all? The method documentation first of all says

   * We must mark this method as belonging to the special legacy group because
   * it might trigger an E_USER_DEPRECATED error during coverage annotation
   * validation.

then the comment in the body says the opposite

      // Change the error handler to ensure deprecation messages are not
      // triggered.

so surely at least one of the error handler and @group legacy is redundant here?

#2933991: Deprecation tests fail when all PHPUnit tests are run via PHPUnit was where this was first introduced.

Rerolled #9

Locally I tried to reproduce the issue in #2933991: Deprecation tests fail when all PHPUnit tests are run via PHPUnit but was not successful. Selected output is as follows:

$ ddev exec vendor/bin/phpunit -c ./core --testsuite unit
PHPUnit 9.5.11 by Sebastian Bergmann and contributors.

Testing 
...........................................................    59 / 19334 (  0%)
...........................................................   118 / 19334 (  0%)
...........................................................   177 / 19334 (  0%)

........................................................... 16166 / 19334 ( 83%)
........................................................... 16225 / 19334 ( 83%)
....S.......................S.............................. 16284 / 19334 ( 84%)
........S................drupal/core-composer-scaffold contains a Composer plugin which is currently not in your allow-plugins config. See https://getcomposer.org/allow-plugins
Do you trust "drupal/core-composer-scaffold" to execute code and wish to enable it now? (writes "allow-plugins" to composer.json) [y,n,d,? ] y
.................................. 16343 / 19334 ( 84%)
I...I...................................................... 16402 / 19334 ( 84%)
........................................................... 16461 / 19334 ( 85%)
........................................................... 16520 / 19334 ( 85%)

........................................................... 19234 / 19334 ( 99%)
........................................................... 19293 / 19334 ( 99%)
.........................................                   19334 / 19334 (100%)

Time: 04:27.184, Memory: 336.00 MB

There was 1 failure:

1) Drupal\Tests\Core\Test\PhpUnitCliTest::testFunctionalTestDebugHtmlOutput
Failed asserting that 'PHPUnit 9.5.11 by Sebastian Bergmann and contributors.\n
\n
Runtime:       PHP 8.0.13\n
Configuration: /var/www/html/drupal/core/phpunit.xml.dist\n
\n
Testing Drupal\Tests\image\Functional\ImageDimensionsTest\n
.                                                                   1 / 1 (100%)\n
\n
Time: 00:05.966, Memory: 4.00 MB\n
\n
OK (1 test, 60 assertions)\n
' contains "HTML output was generated".

/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/Constraint/Constraint.php:121
/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/Constraint/Constraint.php:55
/var/www/html/drupal/core/tests/Drupal/Tests/Core/Test/PhpUnitCliTest.php:52
/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/TestResult.php:726
/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/TestSuite.php:678
/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/TestSuite.php:678
/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/TestSuite.php:678
/var/www/html/drupal/vendor/phpunit/phpunit/src/Framework/TestSuite.php:678
/var/www/html/drupal/vendor/phpunit/phpunit/src/TextUI/TestRunner.php:670
/var/www/html/drupal/vendor/phpunit/phpunit/src/TextUI/Command.php:143
/var/www/html/drupal/vendor/phpunit/phpunit/src/TextUI/Command.php:96

FAILURES!
Tests: 19334, Assertions: 36696, Failures: 1, Skipped: 6, Incomplete: 3.

Legacy deprecation notices (5)
Failed to execute command vendor/bin/phpunit -c ./core --testsuite unit: exit status 1

In other words I ran into #3255749: Composer v2.2 prompts to authorize plugins and PhpUnitCliTest::testFunctionalTestDebugHtmlOutput failed for some reason, but I did not run into any issues with deprecations as per the original report in #2933991: Deprecation tests fail when all PHPUnit tests are run via PHPUnit.

Therefore as far as I can see this code is redundant, presumably due to changes either in PHPUnit or the Symfony PHPUnit bridge, and can be removed.

@mondrake I don't think so because we skip all processing if coverage reports are enabled:

  private function checkValidCoversForTest(TestCase $test) {
    // If we're generating a coverage report already, don't do anything here.
    if ($test->getTestResultObject() && $test->getTestResultObject()->getCollectCodeCoverageInformation()) {
      return;
    }

BROWSERTEST_OUTPUT_DIRECTORY was not set which is why PhpUnitCliTest failed. Maybe we should skip that test if it would fail because of that? edit: there is a skip already but it is too strict, in my case it is an empty string and not FALSE.

Addressed #16, also took the opportunity to refactor away isTestSuite() as it seems pointless.

Opened #3264764: PhpUnitCliTest::testFunctionalTestDebugHtmlOutput fails if BROWSERTEST_OUTPUT_DIRECTORY is an empty string