Pub/Sub unit tests

Demonstrates how to unit test a function triggered by Pub/Sub.

Code sample

C#

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Testing;
using Google.Events.Protobuf.Cloud.PubSub.V1;
using Microsoft.Extensions.Logging;
using System;
using System.Threading;
using System.Threading.Tasks;
using Xunit;

namespace HelloWorld.Tests;

public class HelloPubSubUnitTest
{
    [Fact]
    public async Task MessageWithTextData()
    {
        var data = new MessagePublishedData { Message = new PubsubMessage { TextData = "PubSub user" } };
        var cloudEvent = new CloudEvent
        {
            Type = MessagePublishedData.MessagePublishedCloudEventType,
            Source = new Uri("//pubsub.googleapis.com", UriKind.RelativeOrAbsolute),
            Id = Guid.NewGuid().ToString(),
            Time = DateTimeOffset.UtcNow,
            Data = data
        };

        var logger = new MemoryLogger<HelloPubSub.Function>();
        var function = new HelloPubSub.Function(logger);
        await function.HandleAsync(cloudEvent, data, CancellationToken.None);

        var logEntry = Assert.Single(logger.ListLogEntries());
        Assert.Equal("Hello PubSub user", logEntry.Message);
        Assert.Equal(LogLevel.Information, logEntry.Level);
    }

    [Fact]
    public async Task MessageWithoutTextData()
    {
        var data = new MessagePublishedData
        {
            Message = new PubsubMessage { Attributes = { { "key", "value" } } }
        };
        var cloudEvent = new CloudEvent
        {
            Type = MessagePublishedData.MessagePublishedCloudEventType,
            Source = new Uri("//pubsub.googleapis.com", UriKind.RelativeOrAbsolute),
            Id = Guid.NewGuid().ToString(),
            Time = DateTimeOffset.UtcNow
        };

        var logger = new MemoryLogger<HelloPubSub.Function>();
        var function = new HelloPubSub.Function(logger);
        await function.HandleAsync(cloudEvent, data, CancellationToken.None);

        var logEntry = Assert.Single(logger.ListLogEntries());
        Assert.Equal("Hello world", logEntry.Message);
        Assert.Equal(LogLevel.Information, logEntry.Level);
    }
}

Go

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

package helloworld

import (
	"context"
	"io/ioutil"
	"log"
	"os"
	"testing"
)

func TestHelloPubSub(t *testing.T) {
	tests := []struct {
		data string
		want string
	}{
		{want: "Hello, World!\n"},
		{data: "Go", want: "Hello, Go!\n"},
	}
	for _, test := range tests {
		r, w, _ := os.Pipe()
		log.SetOutput(w)
		originalFlags := log.Flags()
		log.SetFlags(log.Flags() &^ (log.Ldate | log.Ltime))

		m := PubSubMessage{
			Data: []byte(test.data),
		}
		HelloPubSub(context.Background(), m)

		w.Close()
		log.SetOutput(os.Stderr)
		log.SetFlags(originalFlags)

		out, err := ioutil.ReadAll(r)
		if err != nil {
			t.Fatalf("ReadAll: %v", err)
		}
		if got := string(out); got != test.want {
			t.Errorf("HelloPubSub(%q) = %q, want %q", test.data, got, test.want)
		}
	}
}

Java

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import static com.google.common.truth.Truth.assertThat;

import com.google.common.testing.TestLogHandler;
import functions.eventpojos.PubsubMessage;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.logging.Logger;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * Unit tests for main.java.com.example.functions.helloworld.HelloPubSub.
 */
@RunWith(JUnit4.class)
public class HelloPubSubTest {

  private HelloPubSub sampleUnderTest;
  private static final Logger logger = Logger.getLogger(HelloPubSub.class.getName());

  private static final TestLogHandler LOG_HANDLER = new TestLogHandler();

  @Before
  public void setUp() {
    sampleUnderTest = new HelloPubSub();
    logger.addHandler(LOG_HANDLER);
    LOG_HANDLER.clear();
  }

  @Test
  public void helloPubSub_shouldPrintName() {
    PubsubMessage pubSubMessage = new PubsubMessage();
    pubSubMessage.setData(Base64.getEncoder().encodeToString(
        "John".getBytes(StandardCharsets.UTF_8)));
    sampleUnderTest.accept(pubSubMessage, null);

    String logMessage = LOG_HANDLER.getStoredLogRecords().get(0).getMessage();
    assertThat("Hello John!").isEqualTo(logMessage);
  }

  @Test
  public void helloPubSub_shouldPrintHelloWorld() {
    PubsubMessage pubSubMessage = new PubsubMessage();
    sampleUnderTest.accept(pubSubMessage, null);

    String logMessage = LOG_HANDLER.getStoredLogRecords().get(0).getMessage();
    assertThat("Hello world!").isEqualTo(logMessage);
  }
}

Node.js

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

const assert = require('assert');
const uuid = require('uuid');
const sinon = require('sinon');

const {helloPubSub} = require('..');

const stubConsole = function () {
  sinon.stub(console, 'error');
  sinon.stub(console, 'log');
};

const restoreConsole = function () {
  console.log.restore();
  console.error.restore();
};

beforeEach(stubConsole);
afterEach(restoreConsole);

it('helloPubSub: should print a name', () => {
  // Create mock Pub/Sub event
  const name = uuid.v4();
  const event = {
    data: Buffer.from(name).toString('base64'),
  };

  // Call tested function and verify its behavior
  helloPubSub(event);
  assert.ok(console.log.calledWith(`Hello, ${name}!`));
});

PHP

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

namespace Google\Cloud\Samples\Functions\HelloworldPubsub\Test;

use CloudEvents\V1\CloudEventImmutable;
use CloudEvents\V1\CloudEventInterface;
use PHPUnit\Framework\TestCase;

/**
 * Class SampleUnitTest.
 *
 * Unit test for 'Helloworld Pub/Sub' Cloud Function.
 */
class SampleUnitTest extends TestCase
{
    /**
     * Include the Cloud Function code before running any tests.
     *
     * @see https://phpunit.readthedocs.io/en/latest/fixtures.html
     */
    public static function setUpBeforeClass(): void
    {
        require_once __DIR__ . '/index.php';
    }

    public function dataProvider()
    {
        return [
            [
                'cloudevent' => new CloudEventImmutable(
                    uniqId(), // id
                    'pubsub.googleapis.com', // source
                    'google.cloud.pubsub.topic.v1.messagePublished', // type
                    [
                        'data' => base64_encode('John')
                    ]
                ),
                'expected' => 'Hello, John!'
            ],
        ];
    }

    /**
     * @dataProvider dataProvider
     */
    public function testFunction(
        CloudEventInterface $cloudevent,
        string $expected
    ): void {
        // Capture function output by overriding the function's logging behavior.
        // The 'LOGGER_OUTPUT' environment variable must be used in your function:
        //
        // $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');
        // fwrite($log, 'Log Entry');
        putenv('LOGGER_OUTPUT=php://output');
        helloworldPubsub($cloudevent);
        // Provided by PHPUnit\Framework\TestCase.
        $actual = $this->getActualOutput();

        // Test that output includes the expected value.
        $this->assertStringContainsString($expected, $actual);
    }
}

Python

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import base64

from unittest import mock

import main


mock_context = mock.Mock()
mock_context.event_id = "617187464135194"
mock_context.timestamp = "2019-07-15T22:09:03.761Z"
mock_context.resource = {
    "name": "projects/my-project/topics/my-topic",
    "service": "pubsub.googleapis.com",
    "type": "type.googleapis.com/google.pubsub.v1.PubsubMessage",
}


def test_print_hello_world(capsys):
    data = {}

    # Call tested function
    main.hello_pubsub(data, mock_context)
    out, err = capsys.readouterr()
    assert "Hello World!" in out


def test_print_name(capsys):
    name = "test"
    data = {"data": base64.b64encode(name.encode())}

    # Call tested function
    main.hello_pubsub(data, mock_context)
    out, err = capsys.readouterr()
    assert f"Hello {name}!\n" in out

Ruby

To authenticate to Cloud Functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

require "minitest/autorun"
require "functions_framework/testing"
require "base64"

describe "functions_helloworld_pubsub" do
  include FunctionsFramework::Testing

  let(:resource_type) { "type.googleapis.com/google.pubsub.v1.PubsubMessage" }
  let(:source) { "//pubsub.googleapis.com/projects/sample-project/topics/gcf-test" }
  let(:type) { "google.cloud.pubsub.topic.v1.messagePublished" }

  it "prints a name" do
    load_temporary "helloworld/pubsub/app.rb" do
      payload = { "@type" => resource_type, "message" => { "data" => Base64.encode64("Ruby") } }
      event = make_cloud_event payload, source: source, type: type
      _out, err = capture_subprocess_io do
        # Call tested function
        call_event "hello_pubsub", event
      end
      assert_match(/Hello, Ruby!/, err)
    end
  end

  it "prints hello world" do
    load_temporary "helloworld/pubsub/app.rb" do
      payload = { "@type" => resource_type, "message" => { "data" => nil } }
      event = make_cloud_event payload, source: source, type: type
      _out, err = capture_subprocess_io do
        # Call tested function
        call_event "hello_pubsub", event
      end
      assert_match(/Hello, World!/, err)
    end
  end
end

What's next

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