diff --git a/src/agent/debuglet.js b/src/agent/debuglet.js
index 5b19e5d7..86b768e8 100644
--- a/src/agent/debuglet.js
+++ b/src/agent/debuglet.js
@@ -96,7 +96,7 @@ module.exports = Debuglet;
  */
 function Debuglet(debug, config) {
   /** @private {object} */
-  this.config_ = this.normalizeConfig_(config);
+  this.config_ = Debuglet.normalizeConfig_(config);
 
   /** @private {Debug} */
   this.debug_ = debug;
@@ -139,7 +139,7 @@ function Debuglet(debug, config) {
 
 util.inherits(Debuglet, EventEmitter);
 
-Debuglet.prototype.normalizeConfig_ = function(config) {
+Debuglet.normalizeConfig_ = function(config) {
   var envConfig = {
     logLevel: process.env.GCLOUD_DEBUG_LOGLEVEL,
     serviceContext: {
diff --git a/test/test-debuglet.js b/test/test-debuglet.js
index 9e328ad3..d9bc26e3 100644
--- a/test/test-debuglet.js
+++ b/test/test-debuglet.js
@@ -59,17 +59,15 @@ describe('Debuglet', function() {
     afterEach(function() { nock.cleanAll(); });
 
     it('should merge config correctly', function() {
-      var debug = require('../src/debug.js')();
-
       var testValue = 2 * defaultConfig.capture.maxExpandFrames;
       var config = {capture: {maxExpandFrames: testValue}};
-      var debuglet = new Debuglet(debug, config);
 
+      var mergedConfig = Debuglet.normalizeConfig_(config);
+      var compareConfig = Debuglet.normalizeConfig_();
       // The actual config should be exactly defaultConfig with only
       // maxExpandFrames adjusted.
-      var compareConfig = extend(true, {}, defaultConfig);
       compareConfig.capture.maxExpandFrames = testValue;
-      assert.deepEqual(debuglet.config_, compareConfig);
+      assert.deepEqual(mergedConfig, compareConfig);
     });
 
     it('should not start when projectId is not available', function(done) {