Add test coverage

Author: dereuromark

composer.json

@@ -13,7 +13,7 @@
 	],
 	"require": {
 		"php": ">=7.3",
-		"php-collective/code-sniffer": "dev-master",
+		"php-collective/code-sniffer": "^0.1.0",
 		"slevomat/coding-standard": "^8.3.0",
 		"squizlabs/php_codesniffer": "^3.7.0"
 	},