Update README with PHPUnit instructions

README.md

@@ -242,6 +242,12 @@ $ vendor/bin/phing compile
 
 This compile process clones the [libphonenumber](https://github.com/google/libphonenumber) project at the version specified in [METADATA-VERSION.txt](METADATA-VERSION.txt).
 
+### Running tests
+
+This project uses [PHPUnit Bridge](https://symfony.com/doc/current/components/phpunit_bridge.html) to maintain compatibility for the supported PHP versions.
+
+To run the tests locally, run the `./phpunit` script.
+
 ## Integration with frameworks
 
 Other packages exist that integrate libphonenumber-for-php into frameworks.

composer.json

@@ -77,5 +77,8 @@
     "branch-alias": {
       "dev-master": "8.x-dev"
     }
+  },
+  "scripts": {
+    "test": "./phpunit"
   }
 }