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Bootstrapping a Killer Test System


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Our API is getting more and more complex. And doing manually testing is not a great long-term plan. So let's install some tools to get a killer test setup.

Installing the test-pack

Step one: at your terminal run:

composer require test

This is a flex alias for a package called symfony/test-pack. Remember: packs are shortcut packages that actually install a bunch of other packages. For example, when this finishes... and we check out composer.json, you can see down in require-dev that this added PHPUnit itself as well as a few other tools from Symfony to help testing:

102 lines | composer.json
// ... lines 2 - 87
"require-dev": {
// ... line 89
"phpunit/phpunit": "^9.5",
"symfony/browser-kit": "6.2.*",
"symfony/css-selector": "6.2.*",
// ... lines 93 - 95
"symfony/phpunit-bridge": "^6.2",
// ... lines 97 - 99

It also executed a recipe which added a number of files. We have phpunit.xml.dist, a tests/ directory, .env.test for test-specific environment variables and even a little bin/phpunit executable shortcut that we'll use to run our tests.

Hello browser Library

No surprise, Symfony has tools for testing and these can be used to test an API. Heck, API Platform even has their own tools built on top of those to make testing an API even easier. And yet, I'm going to be stubborn and use a totally different tool that I've fallen in love with.

It's called Browser, and it's also built on top of Symfony's testing tools: almost like a nicer interface above that strong base. It's just... super fun to use. Browser gives us a fluid interface that can be used for testing web apps, like you see here, or testing APIs. It can also can be used to test pages that use JavaScript.

Let's get this guy installed. Copy the composer require line, spin back over and run that:

composer require zenstruck/browser --dev

While that's doing its thing, it's optional, but there's an "extension" that you can add to phpunit.xml.dist. Add it down here on the bottom:

47 lines | phpunit.xml.dist
// ... lines 1 - 3
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
// ... lines 11 - 35
<extension class="Zenstruck\Browser\Test\BrowserExtension" />
// ... lines 39 - 45

In the future, if you're using PHPUnit 10, this will likely be replaced by some listener config.

This adds a few extra features to browser. Like, when a test fails, it will automatically save the last response to a file. We'll see this soon. And if you're using JavaScript testing, it'll take screenshots of failures!

Creating our First Test

Ok, we're ready for our first test. In the tests/ directory, it doesn't matter how you organize things, but I'm going to create a Functional/ directory because we're going to be making functional tests to our API. Yup, we'll literally create an API client, make GET or POST requests and then assert that we get back the correct output.

Create a new class called DragonTreasureResourceTest. A normal test extends TestCase from PHPUnit. But make this extend KernelTestCase: a class from Symfony that extends TestCase... but gives us access to Symfony's engine:

// ... lines 1 - 2
namespace App\Tests\Functional;
use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
class DragonTreasureResourceTest extends KernelTestCase

Let's start by testing the GET collection endpoint to make sure we get back the data we expect. To activate the browser library, at the top, add a trait with use HasBrowser:

// ... lines 1 - 5
use Zenstruck\Browser\Test\HasBrowser;
class DragonTreasureResourceTest extends KernelTestCase
use HasBrowser;
// ... lines 11 - 18

Next, add a new test method: public function, how about testGetCollectionOfTreasures()... which will return void:

// ... lines 1 - 7
class DragonTreasureResourceTest extends KernelTestCase
// ... lines 10 - 11
public function testGetCollectionOfTreasures(): void
// ... lines 14 - 17

Using browser is dead simple thanks to that trait: $this->browser(). Now we can make GET, POST, PATCH or whatever request we want. Make a GET request to /api/treasures and then, just to see what that looks like, use this nifty ->dump() function:

// ... lines 1 - 7
class DragonTreasureResourceTest extends KernelTestCase
// ... lines 10 - 11
public function testGetCollectionOfTreasures(): void

Running our Tests through the symfony Binary

How cool is that? Let's see what it looks like. To execute our test, we could run:

php ./vendor/bin/phpunit

That works just fine. But one of the recipes also added a shortcut file:

php bin/phpunit

When we run that, ooh, let's see. The dump() did happen: it dumped out the response... which was some sort of error. It says:

SQLSTATE: connection to server port 5432 failed.

Hmm, it can't connect to our database. Our database is running via a Docker container... and then, because we're using the symfony web server, when we use the site via a browser, the symfony web server detects the Docker container and sets the DATABASE_URL environment variable for us. That's how our API has been able to talk to the Docker database.

When we've run commands that need to talk to the database, we've been running them like symfony console make:migration... because when we execute things through symfony, it adds the DATABASE_URL environment variable... and then runs the command.

So, when we simply run php bin/phpunit... the real DATABASE_URL is missing. To fix that, run:

symfony php bin/phpunit

It's the same thing... except it lets symfony add the DATABASE_URL environment variable. And now... we see the dump again! Scroll to the top. Better! Now the error says:

Database app_test does not exist.

Test-Specific Database

Interesting. To understand what's happening, open config/packages/doctrine.yaml. Scroll down to a when@test section. This is cool: when we're in the test environment, there's a bit of config called dbname_suffix. Thanks to this, Doctrine will take our normal database name and add _test to it:

44 lines | config/packages/doctrine.yaml
// ... lines 1 - 18
# "TEST_TOKEN" is typically set by ParaTest
dbname_suffix: '_test%env(default::TEST_TOKEN)%'
// ... lines 24 - 44

This next part is specific to a library called ParaTest where you can run tests in parallel. Since we're not using that, it's just an empty string and not something we need to worry about.

Anyway, that's how we end up with an _test at the end of our database name. And we want that! We don't want our dev and test environments to use the same database because it gets annoying when they run over each other's data.

By the way, if you're not using the symfony Binary and Docker setup... and you're configuring your database manually, be aware that in the test environment, the .env.local file is not read:

7 lines | .env.test
# define your env variables for the test env here

The test environment is special: it skips reading .env.local and only reads .env.test. You can also create a .env.test.local for env vars that are read in the test environment but that won't be committed to your repository.

The ResetDatabaseTrait

Ok, in the test environment, we're missing the database. We could easily fix this by running:

symfony console doctrine:database:create --env=test

But that's way too much work. Instead, add one more trait to our test class: use ResetDatabase:

// ... lines 1 - 6
use Zenstruck\Foundry\Test\ResetDatabase;
class DragonTreasureResourceTest extends KernelTestCase
// ... line 11
use ResetDatabase;
// ... lines 13 - 20

This comes from Foundry: the library we've been using to create dummy fixtures via the factory classes. ResetDatabase is amazing. It automatically makes sure that the database is cleared before each test. So if you have two tests, your second test isn't going to mess up because of some data that the first test added.

It's also going to create the database automatically for us. Check it out. Run

symfony php bin/phpunit

again and check out the dump. That's our response! It's our beautiful JSON-LD! We don't have any items in the collection yet, but it is working.

And notice that, when we make this request, we are not sending an Accept header on the request. Remember, when we use the Swagger UI... it actually does send an Accept header that advertises that we want application/ld+json.

We can add that to our test if we want. But if we pass nothing, we get JSON-LD back because that's the default format of our API.

Next: let's properly finish this test, including seeding the database with data and learning about Browser's API assertions.