Build updates. (#462)

Author: jmdobry

monitoring/snippets/package.json

@@ -14,8 +14,7 @@
   "scripts": {
     "lint": "samples lint",
     "pretest": "npm run lint",
-    "system-test": "ava -T 3m --verbose system-test/*.test.js",
-    "test": "npm run system-test"
+    "test": "samples test run --cmd ava -- -T 3m --verbose system-test/*.test.js"
   },
   "dependencies": {
     "@google-cloud/monitoring": "0.2.2",