diff --git a/composer.json b/composer.json
index b79a2fc..8a68881 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,7 @@
         "friendsofphp/php-cs-fixer": "^3",
         "php-di/php-di": "^6",
         "phpstan/phpstan": "^1",
-        "phpunit/phpunit": "^6 || ^7",
+        "phpunit/phpunit": "^6 || ^7 || ^12",
         "squizlabs/php_codesniffer": "^3"
     },
     "autoload": {