diff --git a/composer.json b/composer.json
index f7ea131..b9ef099 100644
--- a/composer.json
+++ b/composer.json
@@ -18,14 +18,16 @@
         "php": ">=5.3.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "4.0.*"
+        "phpunit/phpunit": "~4.0"
     },
     "support": {
         "issues": "https://github.com/danielstjules/Stringy/issues",
         "source": "https://github.com/danielstjules/Stringy"
     },
     "autoload": {
-        "psr-4": { "Stringy\\": "src/" },
+        "psr-4": { "Stringy\\": "src/" }
+    },
+    "autoload-dev": {
         "classmap": [ "tests" ]
     }
 }