[9.x] Enable trait setUp/tearDown for tests traits.

[DarkGhostHunter]

When dealing this testing, sometimes you may want to share initialization between many Test Classes. For example, you may want to set up a Post with an User and three comments.

public function setUp(): void
{
    parent::setUp();

    $this->post = Post::factory()->hasComments(3)->createOne();
}

public function tearDown(): void
{
    parent:tearDown();

    $this->post = null;
}

Doing this across many Tests becomes cumbersome, specially if you need to mix additional setUp and tearDown procedures.

Instead, we can use the same technique of trait initialization and booting in Models, but in tests.

Implementation

On the setUpTraits() method, we can setup the trait saving setUp{trait} and tearDown{trait} into a callback that later can be called by the application.

protected function setUpTraits(): array
{
    foreach ($traits = class_uses_recursive(static::class)) as $trait) {
        if (method_exists($this, $name = 'setUp' . $trait)) {
            $this->afterApplicationCreated([$this, $name]);
        }

        if (method_exists($this, $name = 'tearDown' . $trait)) {
            $this->beforeApplicationDestroyed([$this, $name]);
        }
    }

    return $traits;
}

This would mean that traits like RefreshDatabase, DatabaseMigrations, DatabaseTransactions, WithoutMiddleware, WithoutEvents and WithFaker would change their booting methods, making it a breaking change for Laravel 9.x.

Example

With the above, we can create a trait that creates a Post with an User and 3 Comments, keeping the implementation clean in the Test Class:

class ExampleTest extends TestCase
{
    use CreatePost;

    public function test_post_sees_comments(): void
    {
        $this->get('post/' . $this->post->id)
            ->assertOk();
    }
}

trait CreatePost
{
    protected Post $post;

    protected function setUpCreatePost(): void
    {
        $this->post = Pots::factory()->hasComments(3)->createOne();
    }

    protected function setUpCreatePost(): void
    {
        $this->post = null;
    }
}

[crynobone]

I believe you already PR this and merged.