./vendor/bin/phpunit -c core/phpunit.xml core/tests/Drupal/Tests/Core/DrupalTest.php
PHPUnit 8.5.31 by Sebastian Bergmann and contributors.

Testing Drupal\Tests\Core\DrupalTest
.................................F                                34 / 34 (100%)

Time: 1.43 seconds, Memory: 10.00 MB

There was 1 failure:

1) Drupal\Tests\Core\DrupalTest::testMajorVersion
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'9'
+'10'

/Applications/MAMP-common/htdocs/drupal-9_1/vendor/phpunit/phpunit/src/Framework/Constraint/IsEqual.php:100
/Applications/MAMP-common/htdocs/drupal-9_1/core/tests/Drupal/Tests/Core/DrupalTest.php:441
/Applications/MAMP-common/htdocs/drupal-9_1/vendor/phpunit/phpunit/src/Framework/TestResult.php:703
/Applications/MAMP-common/htdocs/drupal-9_1/vendor/phpunit/phpunit/src/Framework/TestSuite.php:620
/Applications/MAMP-common/htdocs/drupal-9_1/vendor/phpunit/phpunit/src/TextUI/TestRunner.php:647
/Applications/MAMP-common/htdocs/drupal-9_1/vendor/phpunit/phpunit/src/TextUI/Command.php:235
/Applications/MAMP-common/htdocs/drupal-9_1/vendor/phpunit/phpunit/src/TextUI/Command.php:194

FAILURES!
Tests: 34, Assertions: 74, Failures: 1.