diff --git a/composer.json b/composer.json
index 93b8f31..cfb308e 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,8 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^5.7",
-        "squizlabs/php_codesniffer": "^3.0"
+        "squizlabs/php_codesniffer": "^3.0",
+	"sminnee/phpunit-mock-objects": "^3.4.5"
     },
     "extra": {
         "branch-alias": {