diff --git a/functions/helloworld/index.js b/functions/helloworld/index.js
index ab2851492c..270cbd1fd1 100644
--- a/functions/helloworld/index.js
+++ b/functions/helloworld/index.js
@@ -108,7 +108,7 @@ exports.helloGCS = (event, callback) => {
 exports.helloGCSGeneric = (event, callback) => {
   const file = event.data;
 
-  console.log(`  Event ${event.eventId}`);
+  console.log(`  Event: ${event.eventId}`);
   console.log(`  Event Type: ${event.eventType}`);
   console.log(`  Bucket: ${file.bucket}`);
   console.log(`  File: ${file.name}`);
diff --git a/functions/helloworld/test/sample.unit.http.test.js b/functions/helloworld/test/sample.unit.http.test.js
index e08d1d6ec8..b495c3ca68 100644
--- a/functions/helloworld/test/sample.unit.http.test.js
+++ b/functions/helloworld/test/sample.unit.http.test.js
@@ -21,7 +21,7 @@ const uuid = require(`uuid`);
 const helloHttp = require(`..`).helloHttp;
 
 test(`helloHttp: should print a name`, t => {
-  // Initialize mocks
+  // Mock ExpressJS 'req' and 'res' parameters
   const name = uuid.v4();
   const req = {
     body: {
@@ -39,7 +39,7 @@ test(`helloHttp: should print a name`, t => {
 });
 
 test(`helloHttp: should print hello world`, t => {
-  // Initialize mocks
+  // Mock ExpressJS 'req' and 'res' parameters
   const req = {
     body: {}
   };
diff --git a/functions/log/index.js b/functions/log/index.js
index 62e51cbe54..809de6d0b0 100644
--- a/functions/log/index.js
+++ b/functions/log/index.js
@@ -16,10 +16,10 @@
 'use strict';
 
 // [START functions_log_helloworld]
-exports.helloWorld = (event, callback) => {
+exports.helloWorld = (req, res) => {
   console.log('I am a log entry!');
   console.error('I am an error!');
-  callback();
+  res.end();
 };
 // [END functions_log_helloworld]
 
diff --git a/functions/log/test/index.test.js b/functions/log/test/index.test.js
index 8c6184c26e..fc9ff46c7b 100644
--- a/functions/log/test/index.test.js
+++ b/functions/log/test/index.test.js
@@ -57,14 +57,14 @@ test.afterEach.always(tools.restoreConsole);
 
 test.serial(`should write to log`, (t) => {
   const expectedMsg = `I am a log entry!`;
-  const callback = sinon.stub();
+  const res = { end: sinon.stub() };
 
-  getSample().program.helloWorld({}, callback);
+  getSample().program.helloWorld({}, res);
 
   t.is(console.log.callCount, 1);
   t.deepEqual(console.log.firstCall.args, [expectedMsg]);
-  t.is(callback.callCount, 1);
-  t.deepEqual(callback.firstCall.args, []);
+  t.is(res.end.callCount, 1);
+  t.deepEqual(res.end.firstCall.args, []);
 });
 
 test.serial(`getLogEntries: should retrieve logs`, (t) => {