diff --git a/package.json b/package.json
index fde53e3..8e3a2d2 100644
--- a/package.json
+++ b/package.json
@@ -24,7 +24,7 @@
   ],
   "homepage": "https://github.com/fastify/fastify-oauth2#readme",
   "devDependencies": {
-    "fastify": "^1.5.0",
+    "fastify": "^2.0.1",
     "nock": "^9.3.2",
     "pre-commit": "^1.2.2",
     "simple-get": "^3.0.2",
diff --git a/test.js b/test.js
index a6d4556..e412e72 100644
--- a/test.js
+++ b/test.js
@@ -318,6 +318,6 @@ t.test('already decorated', t => {
       callbackUri: '/callback'
     })
     .ready(err => {
-      t.strictSame(err.message, 'The decorator \'githubOAuth2\' has already been added!')
+      t.strictSame(err.message, 'FST_ERR_DEC_ALREADY_PRESENT: The decorator \'githubOAuth2\' has already been added!')
     })
 })