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15.

JSON Test Assertions & Seeding the Database

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Let's make this test real with data and assertions.

There are two main ways to do assertions with Browser. First, it comes with a bunch of built-in methods to help, like ->assertJson(). Or... you can always just grab the JSON that comes back from an endpoint and check things using the built-in PHPUnit assertions you know and love. We'll see both.

Let's start by checking ->assertJson():

// ... lines 1 - 8
class DragonTreasureResourceTest extends KernelTestCase
{
// ... lines 11 - 13
public function testGetCollectionOfTreasures(): void
{
$this->browser()
->get('/api/treasures')
// ... line 18
->assertJson()
;
}
}

When we run that:

symfony php bin/phpunit

It passes! Cool! We know that this response should have a hydra:totalItems property set to the number of results. Right now, our database is empty... but we can at least assert that it matches zero.

To do that, use ->assertJsonMatches().

This is a special method from Browser that uses a special syntax that allows us to read different parts off the JSON. We'll dig into it in a minute.

But this one is simple: assert that hydra:totalItems equals 0:

// ... lines 1 - 8
class DragonTreasureResourceTest extends KernelTestCase
{
// ... lines 11 - 13
public function testGetCollectionOfTreasures(): void
{
$this->browser()
// ... lines 17 - 18
->assertJson()
->assertJsonMatches('hydra:totalItems', 0)
;
}
}

When we try this:

symfony php bin/phpunit

It fails! But with a great error:

mtdowling/jmespath.php is required to search JSON

Hello JMESPath

Ah, we need to install that! Copy the composer require line, find your terminal, and run it:

composer require mtdowling/jmespath.php --dev

This "JMESPath" thing is actually super cool: it's a "query language" for reading different parts of any JSON. For example, if this is your JSON and you want to read the a key, just say a. Simple.

But you can also do deeper, like: a.b.c.d. Or, get crazier: grab the 1 index, or grab a.b.c, then the 0 index, .d, the 1 index then the 0 index. You can even slice the array in different ways. Basically... you can go nuts.

But we're not going to lose our minds with this. It's a handy syntax... but if things get too complex, we can always test the JSON manually, which we'll do in a bit.

Anyway, now that we have the library installed, let's run the test again.

symfony php bin/phpunit

It still fails! With a weird error:

Syntax error at character 5 hydra:totalItems.

Unfortunately, the : is a special character inside of JMESPath. So whenever we have a :, we need to put quotes around that key:

// ... lines 1 - 8
class DragonTreasureResourceTest extends KernelTestCase
{
// ... lines 11 - 13
public function testGetCollectionOfTreasures(): void
{
$this->browser()
// ... lines 17 - 19
->assertJsonMatches('"hydra:totalItems"', 0)
;
}
}

Not ideal, but not a huge inconvenience.

Now when we try it:

symfony php bin/phpunit

It passes!

Seeding the Database

But... this isn't a very interesting test: we're just asserting that we get nothing back... because the database is empty. To make our test real, we need data: we need to seed the database with data at the start of the test.

Tip

To use Foundry factories in a test, also add a use Factories; trait to the top of your test class. Things worked without that in this case, but in the future, you'll likely get an error.

Fortunately, Foundry makes that dead-simple. At the top, call DragonTreasureFactory::createMany() and let's create 5 treasures. Now, below, assert that we get 5 results:

// ... lines 1 - 4
use App\Factory\DragonTreasureFactory;
// ... lines 6 - 9
class DragonTreasureResourceTest extends KernelTestCase
{
// ... lines 12 - 14
public function testGetCollectionOfTreasures(): void
{
DragonTreasureFactory::createMany(5);
$this->browser()
// ... lines 20 - 22
->assertJsonMatches('"hydra:totalItems"', 5)
// ... line 24
;
}
}

It's just that simple. And actually, let me put our dump back so we can see the result:

// ... lines 1 - 9
class DragonTreasureResourceTest extends KernelTestCase
{
// ... lines 12 - 14
public function testGetCollectionOfTreasures(): void
{
// ... lines 17 - 18
$this->browser()
// ... line 20
->dump()
// ... line 22
->assertJsonMatches('"hydra:totalItems"', 5)
// ... line 24
;
}
}

Try it now:

symfony php bin/phpunit

It passes! And if you look up, yea! The response has 5 treasures! Dang, that was easy.

Next: let's use JMESPath to assert something more challenging. Then we'll back up and see how we can dig into Browser to give us infinite flexibility - and simplicity - when it comes to testing JSON.