drzfnr0275
2018-05-09 21:50
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如何在Laravel中运行功能测试时模拟服务(或ServiceProvider)?

I'm writing a small API in Laravel, partly for the purposes of learning this framework. I think I have spotted a gaping hole in the docs, but it may be due to my not understanding the "Laravel way" to do what I want.

I am writing an HTTP API to, amongst other things, list, create and delete system users on a Linux server. The structure is like so:

  • Routes to /v1/users connect GET, POST and DELETE verbs to controller methods get, create and delete respectively.
  • The controller App\Http\Controllers\UserController does not actually run system calls, that is done by a service App\Services\Users.
  • The service is created by a ServiceProvider App\Providers\Server\Users that registers a singleton of the service on a deferred basis.
  • The service is instantiated by Laravel automatically and auto-injected into the controller's constructor.

OK, so this all works. I have also written some test code, like so:

public function testGetUsers()
{
    $response = $this->json('GET', '/v1/users');
    /* @var $response \Illuminate\Http\JsonResponse */

    $response
        ->assertStatus(200)
        ->assertJson(['ok' => true, ]);
}

This also works fine. However, this uses the normal bindings for the UserService, and I want to put a dummy/mock in here instead.

I think I need to change my UserService to an interface, which is easy, but I am not sure how to tell the underlying test system that I want it to run my controller, but with a non-standard service. I see App::bind() cropping up in Stack Overflow answers when researching this, but App is not automatically in scope in artisan-generated tests, so it feels like clutching at straws.

How can I instantiate a dummy service and then send it to Laravel when testing, so it does not use the standard ServiceProvider instead?

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2条回答 默认 最新

  • doulu8415 2018-05-09 22:41
    已采纳

    The obvious way is to re-bind the implementation in setUp().

    Make your self a new UserTestCase (or edit the one provided by Laravel) and add:

    abstract class TestCase extends BaseTestCase
    {
        use CreatesApplication;
    
        protected function setUp()
        {
            parent::setUp();
    
            app()->bind(YourService::class, function() { // not a service provider but the target of service provider
                return new YourFakeService();
            });
        }
    }
    
    class YourFakeService {} // I personally keep fakes in the test files itself if they are short
    

    Register providers conditionally based on environment (put this in AppServiceProvider.php or any other provider that you designate for this task - ConditionalLoaderServiceProvider.php or whatever) in register() method

    if (app()->environment('testing')) {
        app()->register(FakeUserProvider::class);
    } else {
        app()->register(UserProvider::class);
    }
    

    Note: drawback is that list of providers is on two places one in config/app.php and one in the AppServiceProvider.php

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  • dsdsds12222 2018-05-09 22:42

    Aha, I have found a temporary solution. I'll post it here, and then explain how it can be improved.

    <?php
    
    namespace Tests\Feature;
    
    use Tests\TestCase;
    use \App\Services\Users as UsersService;
    
    class UsersTest extends TestCase
    {
        /**
         * Checks the listing of users
         *
         * @return void
         */
        public function testGetUsers()
        {
            $this->app->bind(UsersService::class, function() {
                return new UsersDummy();
            });
    
            $response = $this->json('GET', '/v1/users');
    
            $response
                ->assertStatus(200)
                ->assertJson(['ok' => true, ]);
        }
    }
    
    class UsersDummy extends UsersService
    {
        public function listUsers()
        {
            return ['tom', 'dick', 'harry', ];
        }
    }
    

    This injects a DI binding so that the default ServiceProvider does not need to kick in. If I add some debug code to $response like so:

    /* @var $response \Illuminate\Http\JsonResponse */
    print_r($response->getData(true));
    

    then I get this output:

    Array
    (
        [ok] => 1
        [users] => Array
            (
                [0] => tom
                [1] => dick
                [2] => harry
            )
    
    )
    

    This has allowed me to create a test with a boundary drawn around the PHP, and no calls are made to the test box to interact with the user system.

    I will next investigate whether my controller's constructor can be changed from a concrete implementation hint (\App\Services\Users) to an interface, so that my test implementation does not need to extend from the real one.

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