Cloud Storage (2nd Gen) Unit Test

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

Code sample

C#

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

namespace HelloWorld.Tests;

public class HelloGcsUnitTest
{
    [Fact]
    public async Task FileNameIsLogged()
    {
        // Prepare the inputs
        var data = new StorageObjectData { Name = "new-file.txt" };
        var cloudEvent = new CloudEvent
        {
            Type = StorageObjectData.FinalizedCloudEventType,
            Source = new Uri("//storage.googleapis.com", UriKind.RelativeOrAbsolute),
            Id = "1234",
            Data = data
        };
        var logger = new MemoryLogger<HelloGcs.Function>();

        // Execute the function
        var function = new HelloGcs.Function(logger);
        await function.HandleAsync(cloudEvent, data, CancellationToken.None);

        // Check the log results - just the entry starting with "File:".
        var logEntry = Assert.Single(logger.ListLogEntries(), entry => entry.Message.StartsWith("File:"));
        Assert.Equal("File: new-file.txt", logEntry.Message);
        Assert.Equal(LogLevel.Information, logEntry.Level);
    }
}

Go

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package helloworld

import (
	"context"
	"io/ioutil"
	"log"
	"os"
	"strings"
	"testing"
	"time"

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

func TestHelloStorage(t *testing.T) {
	r, w, _ := os.Pipe()
	log.SetOutput(w)
	originalFlags := log.Flags()
	log.SetFlags(log.Flags() &^ (log.Ldate | log.Ltime))

	d := StorageObjectData{
		Name:        "hello_gcs.txt",
		TimeCreated: time.Now(),
	}
	e := event.New()
	e.SetDataContentType("application/json")
	e.SetData(e.DataContentType(), d)

	helloStorage(context.Background(), e)

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

	out, err := ioutil.ReadAll(r)
	if err != nil {
		t.Fatalf("ReadAll: %v", err)
	}
	got := string(out)
	if want := d.Name; strings.Contains(want, got) {
		t.Errorf("HelloStorage = %q, want to contain %q", got, want)
	}
	if want := d.TimeCreated.String(); strings.Contains(want, got) {
		t.Errorf("HelloStorage = %q, want to contain %q", got, want)
	}
}

PHP

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

use CloudEvents\V1\CloudEventImmutable;
use CloudEvents\V1\CloudEventInterface;

use PHPUnit\Framework\TestCase;

/**
 * Class SampleUnitTest.
 *
 * Unit test for 'Helloworld Storage' 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
                    'storage.googleapis.com', // source
                    'google.cloud.storage.object.v1.finalized', // type
                    [
                        'bucket' => 'some-bucket',
                        'metageneration' => '1',
                        'name' => 'folder/friendly.txt',
                        'timeCreated' => '2020-04-23T07:38:57.230Z',
                        'updated' => '2020-04-23T07:38:57.230Z',
                    ] // data
                ),
                'statusCode' => '200',
            ],
        ];
    }

    /**
     * @dataProvider dataProvider
     */
    public function testFunction(CloudEventInterface $cloudevent): 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');
        helloGCS($cloudevent);
        // Provided by PHPUnit\Framework\TestCase.
        $actual = $this->getActualOutput();

        // Test output includes the properties provided in the CloudEvent.
        foreach ($cloudevent->getData() as $property => $value) {
            $this->assertStringContainsString($value, $actual);
        }
        $this->assertStringContainsString($cloudevent->getId(), $actual);
        $this->assertStringContainsString($cloudevent->getType(), $actual);
    }
}

What's next

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