diff --git a/composer.json b/composer.json
index b1d8fe0d..3fd7b831 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,8 @@
         "phpstan/phpstan": "^1.10",
         "phan/phan": "^5.4",
         "phpstan/extension-installer": "^1.2",
-        "phpstan/phpstan-strict-rules": "^1.5"
+        "phpstan/phpstan-strict-rules": "^1.6",
+        "phpunit/phpunit": "^9"
     },
     "config": {
         "allow-plugins": {