update tests

Author: MoamenEltouny

composer.json

@@ -22,7 +22,7 @@
         "php": ">=7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": ">=6.5"
+        "phpunit/phpunit": ">=5.0"
     },
     "autoload": {
         "files": [