added phpunit

composer.json

@@ -20,6 +20,9 @@
 	"require": {
 		"php": ">=5.6.0"
 	},
+	"require-dev": {
+		"phpunit/phpunit": "5.1.*"
+	},
 	"suggest": {
 		"chillerlan/php-googleauth": "*"
 	},