diff --git a/composer.json b/composer.json
index f7cc815..e3059e7 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,8 @@
         "phpunit/phpunit": "^5.7.21 || ^6.5 || ^7.5",
         "phpcompatibility/php-compatibility": "*",
         "squizlabs/php_codesniffer": "3.*",
-        "wp-coding-standards/wpcs": "^2.3.0"
+        "wp-coding-standards/wpcs": "^2.3.0",
+        "yoast/phpunit-polyfills": "^1.0"
     },
     "license": "MIT",
     "authors": [