Cloud Pub/Sub (2nd Gen) Unit Test

Example unit test for a Cloud Pub/Sub-triggered function running on Cloud Functions (2nd Gen).

Code sample

C#

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

package helloworld

import (
	"context"
	"io"
	"log"
	"os"
	"testing"

	"github.com/cloudevents/sdk-go/v2/event"
)

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),
		}
		msg := MessagePublishedData{
			Message: m,
		}
		e := event.New()
		e.SetDataContentType("application/json")
		e.SetData(e.DataContentType(), msg)

		helloPubSub(context.Background(), e)

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

		out, err := io.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)
		}
	}
}

PHP

To authenticate to Cloud Run 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);
    }
}

What's next

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