How to make Laravel's dependency injection work in PHPUnit unit test cases?

Question

Some interfaces and implementations are mapped to be bound to each other in a service provider, however when I try to instantiate a class using Laravel's app() in the context of a unit test, these interface -> implementations don't seem to be registered.

class InterfaceServiceProvider extends ServiceProvider
{
    public const INTERFACE_BINDINGS = [
        \User\Repository::class => \Eloquent\User\Repository::class,
        \User\Role\Repository::class => \Eloquent\User\Role\Repository::class,
    ];

/**
 * Bootstrap services.
 *
 * @return void
 */
    public function boot()
    {
        $this->handleInterfaceBindings();
    }

    private function handleInterfaceBindings(): void
    {
        foreach (self::INTERFACE_BINDINGS as $interface => $implementation) {
            $this->app->bind($interface, $implementation);
        }
    }
}

This service provider is registered in config/app.php.

My test case below returns an error complaining about not being able to instantiate the repository (since I am injecting the interface as a dependency, and I want it to automatically inject the implementation everywhere):

class CheckerTest extends TestCase
{

    private \User\Permission\Checker $model;

    protected function setUp(): void
    {
        $this->model = app(\User\Permission\Checker::class);
    }

    public function testCheckerReturnsTrueWhenPermissionExists(): void
    {
        $permissions = new \User\Permission\Collection();
        $permissions->add(
            (new \User\Permission\Entity(1))
            ->setValue(
                \User\Permission::USER_VIEW->value
            )
        );
        $user = (new \User\Entity('1'))->setPermissions($permissions);

        $result = $this->model->check(
            \User\Permission::USER_VIEW,
            $user
        );

        $this->assertTrue($result);
    }
}

The error to be specific is:

Illuminate\Contracts\Container\BindingResolutionException

Target [User\Repository] is not instantiable while building [\User\Permission\Checker, User\Current].

Clearly the interface -> implementation binding that laravel provides doesnt work in the unit tests, how can I use it? Or is there something in PHPUnit I can use to get around this issue? I dont really want to mock each of the dependencies and inject them one by one as this is just one example but in some cases they go quite a few levels deep.

Answer 1

When you do setUp you have to call parent::setUp(); first...

class CheckerTest extends TestCase
{
    private \User\Permission\Checker $model;

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

        $this->model = app(\User\Permission\Checker::class);
    }

    public function testCheckerReturnsTrueWhenPermissionExists(): void
    {
        $permissions = new \User\Permission\Collection();
        $permissions->add(
            (new \User\Permission\Entity(1))
            ->setValue(
                \User\Permission::USER_VIEW->value
            )
        );
        $user = (new \User\Entity('1'))->setPermissions($permissions);

        $result = $this->model->check(
            \User\Permission::USER_VIEW,
            $user
        );

        $this->assertTrue($result);
    }
}

See how the parent setUp it is still setting up stuff.

---

And, you are binding stuff in the boot method, you should be binding stuff in the register method. More info here.