Cloud Storage unit tests

Demonstrates how to unit test a function triggered by Cloud Storage.

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;
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

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"
	"strings"
	"testing"

	"cloud.google.com/go/functions/metadata"
)

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

	name := "hello_gcs.txt"
	e := GCSEvent{
		Name: name,
	}
	meta := &metadata.Metadata{
		EventID: "event ID",
	}
	ctx := metadata.NewContext(context.Background(), meta)

	HelloGCS(ctx, e)

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

	out, err := io.ReadAll(r)
	if err != nil {
		t.Fatalf("ReadAll: %v", err)
	}

	got := string(out)
	wants := []string{
		"File: " + name,
		"Event ID: " + meta.EventID,
	}
	for _, want := range wants {
		if !strings.Contains(got, want) {
			t.Errorf("HelloGCS(%v) = %q, want to contain %q", e, got, want)
		}
	}
}

Java

To authenticate to Cloud Run 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.GcsEvent;
import functions.eventpojos.MockContext;
import java.util.logging.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * Unit tests for main.java.com.example.functions.helloworld.HelloGcs.
 */
public class HelloGcsTest {
  private static final TestLogHandler LOG_HANDLER = new TestLogHandler();
  private static final Logger logger = Logger.getLogger(HelloGcs.class.getName());

  @Before
  public void beforeTest() throws Exception {
    logger.addHandler(LOG_HANDLER);
  }

  @After
  public void afterTest() {
    LOG_HANDLER.clear();
  }

  @Test
  public void helloGcs_shouldPrintFileName() {
    GcsEvent event = new GcsEvent();
    event.setName("foo.txt");

    MockContext context = new MockContext();
    context.eventType = "google.storage.object.finalize";

    new HelloGcs().accept(event, context);

    String message = LOG_HANDLER.getStoredLogRecords().get(3).getMessage();
    assertThat(message).contains("File: foo.txt");
  }
}

Node.js

To authenticate to Cloud Run 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 {helloGCS} = 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('helloGCS: should print out event', () => {
  // Initialize mocks
  const filename = uuid.v4();
  const eventType = 'google.storage.object.finalize';
  const event = {
    name: filename,
    resourceState: 'exists',
    metageneration: '1',
  };
  const context = {
    eventId: 'g1bb3r1sh',
    eventType: eventType,
  };

  // Call tested function and verify its behavior
  helloGCS(event, context);
  assert.ok(console.log.calledWith(`  File: ${filename}`));
  assert.ok(console.log.calledWith(`  Event Type: ${eventType}`));
});

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\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);
    }
}

Python

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

from unittest import mock

import main


def test_print(capsys):
    name = "test"
    event = {
        "bucket": "some-bucket",
        "name": name,
        "metageneration": "some-metageneration",
        "timeCreated": "0",
        "updated": "0",
    }

    context = mock.MagicMock()
    context.event_id = "some-id"
    context.event_type = "gcs-event"

    # Call tested function
    main.hello_gcs(event, context)
    out, err = capsys.readouterr()
    assert f"File: {name}\n" in out

Ruby

To authenticate to Cloud Run 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 "date"

describe "functions_helloworld_storage" do
  include FunctionsFramework::Testing

  let(:source) { "//storage.googleapis.com/projects/sample-project/buckets/sample-bucket/objects/ruby-rocks.rb" }
  let(:type) { "google.cloud.storage.object.v1.finalized" }

  it "responds to generic event" do
    load_temporary "helloworld/storage/app.rb" do
      timestamp = DateTime.new(2020, 2, 3, 4, 5, 6).rfc3339
      payload = {
        "bucket"         => "sample-bucket",
        "name"           => "ruby-rocks.rb",
        "metageneration" => "1",
        "timeCreated"    => timestamp,
        "updated"        => timestamp
      }
      event = make_cloud_event payload, source: source, type: type
      _out, err = capture_subprocess_io do
        call_event "hello_gcs", event
      end

      assert_match(/Event: /, err)
      assert_match(/Event Type: google.cloud.storage.object.v1.finalized/, err)
      assert_match(/Bucket: sample-bucket/, err)
      assert_match(/File: ruby-rocks.rb/, err)
      assert_match(/Metageneration: 1/, err)
      assert_match(/Created: 2020-02-03T04:05:06\+00:00/, err)
      assert_match(/Updated: 2020-02-03T04:05:06\+00:00/, err)
    end
  end
end

What's next

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