Add custom codesniffer rules

Author: tvdijen

composer.json

@@ -37,7 +37,7 @@
         "simplesamlphp/assert": "^1.0.3"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6 || ^10.0"
+        "simplesamlphp/simplesamlphp-test-framework": "^1.5.2"
     },
     "support": {
         "issues": "https://github.com/simplesamlphp/xml-common/issues",

phpcs.xml

@@ -11,5 +11,6 @@
 
     <!-- This is the rule we inherit from. If you want to exclude some specific rules, see the docs on how to do that -->
     <rule ref="PSR12"/>
+    <rule ref="vendor/simplesamlphp/simplesamlphp-test-framework/phpcs-simplesamlphp.xml"/>
 </ruleset>