Fix test workflow issues with WP_Mock, PHP 7.0 compatibility, and code style

composer.json

@@ -14,10 +14,12 @@
         "php": ">=7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5 || ^8.0 || ^9.0",
+        "phpunit/phpunit": "^6.5 || ^7.5 || ^8.0 || ^9.0",
         "squizlabs/php_codesniffer": "^3.5",
         "wp-coding-standards/wpcs": "^2.3",
-        "dealerdirect/phpcodesniffer-composer-installer": "^0.7.0"
+        "dealerdirect/phpcodesniffer-composer-installer": "^0.7.0",
+        "10up/wp_mock": "0.3.0",
+        "antecedent/patchwork": "^2.1.21"
     },
     "autoload": {
         "psr-4": {