Initial Drupal 11 with DDEV setup

web/core/tests/PHPStan/README.md

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+# Drupal custom PHPStan rules
+
+This directory contains PHPStan rules specifically developed for Drupal.
+
+## Subdirectories
+
+* _Rules_: contains the actual rules.
+* _tests_: contains PHPUnit tests for the rules.
+* _fixtures_: contains fixture files for the PHPUnit tests of the rules.
+
+## Enabling rules
+
+Rules are executed when they are added to the the phpstan.neon(.dist)
+configuration file of a PHPStan scan run. You need to add them under the
+`rules` entry in the file, specifying the fully qualified class name of the
+rule. For example:
+```
+
+rules:
+  - Drupal\PHPStan\Rules\ComponentTestDoesNotExtendCoreTest
+
+```
+
+## Testing rules
+
+PHPStan rules must be tested in the context of the PHPStan testing framework,
+that differs in terms of dependencies from Drupal's one.
+
+Note that for this reason, these tests are run _separately_ from Drupal core
+tests.
+
+A _composer.json_ file is present in this directory, indicating the required
+packages for the execution of the tests. Installing via composer
+```
+$ composer install
+```
+builds a _vendor_ subdirectory that includes all the packages required. Note
+this packages' codebase is totally independent from Drupal core's one.
+
+In the context of this directory, you can then execute the rule tests like
+```
+$ vendor/bin/phpunit tests
+```