I like testing and always find a way to bitch about it whenever i can. So, here we go again.

I have been working on a framework agnostic package called Gbowo for quite some time. Essentially, it is a payment library for this new wave of Stripe like Nigerian payment startups.

Since i like Laravel, support for the framework was baked directly into the package. Obviously, it was totally alienated from the package itself but was on the file tree.

While the package was - and still is - fully tested, the Laravel bridge i wrote didn’t have a single tests. I didn’t like that.

I didn’t want that to ruin my awesome code coverage 0. So i added @codeCoverageIgnore to the files in the bridge package (namespace). There were 3 files in total - a ServiceProvider, a Facade and errm, a Manager.

In the spirit of modularity, I then decided to migrate the bridge to it’s own repository. Then the problem resurfaced. I wasn’t going to create a package without a testsuite. I just couldn’t entertain that thought.

That birthed this blog post.

The Blog Post itself

For the most part of integrating a package into Laravel, we need at least a Facade and a ServiceProvider. Extra classes can also be added. For example, Laravel’s Filesystem package defines extra objects. In the case of the migrated package as mentioned earlier, i had just 3 objects - a Facade, a ServiceProvider and a Manager.

Here is what the service provider looks like :

<?php

namespace Gbowo\Bridge\Laravel;

use Illuminate\Support\ServiceProvider;
use Gbowo\Adapter\Paystack\PaystackAdapter;
use Gbowo\Adapter\Amplifypay\AmplifypayAdapter;

class GbowoServiceProvider extends ServiceProvider
{

    protected $defer = true;

    public function register()
    {
        $this->registerManager();
        $this->registerAdapters();
    }

    protected function registerManager()
    {
        $this->app->singleton('gbowo', function ($app) {
            return new GbowoManager($app);
        });
    }

    protected function registerAdapters()
    {
        $this->app->bind("gbowo.paystack", function () {
            return new PaystackAdapter();
        });

        $this->app->bind("gbowo.amplifypay", function () {
            return new AmplifypayAdapter();
        });

    }

    public function provides()
    {
        return ["gbowo", "gbowo.paystack", "gbowo.amplifypay"];
    }
}

Those adapters are from the core package.

The Manager is used for managing (sic) adapters instance at a transparent level. So here is what it looks like

<?php

namespace Gbowo\Bridge\Laravel;

use Closure;
use Gbowo\GbowoFactory;
use InvalidArgumentException;
use Illuminate\Contracts\Foundation\Application;

class GbowoManager
{

    protected static $supportedAdapters = [
        GbowoFactory::PAYSTACK => GbowoFactory::PAYSTACK,
        GbowoFactory::AMPLIFY_PAY => GbowoFactory::AMPLIFY_PAY
    ];

    protected $customAdapters = [];

    protected $adapters = [];

    protected $app;

    public function __construct(Application $app)
    {
        $this->app = $app;
    }

    public function adapter(string $name = null)
    {
        $adapter = $name ?? $this->getDefaultDriverName();

        return $this->adapters[$adapter] = $this->getAdapter($adapter);
    }

    protected function getDefaultDriverName()
    {
        return $this->app['config']['services.gbowo.default'];
    }

    protected function getAdapter(string $name)
    {
        return isset($this->adapters[$name]) ? $this->adapters[$name] : $this->resolveAdapter($name);
    }

    protected function resolveAdapter(string $name)
    {
        if (isset($this->customAdapters[$name])) {
            return $this->customAdapters[$name]();
        }

        if (!array_key_exists($name, self::$supportedAdapters)) {
            throw new InvalidArgumentException(
                "The specified adapter, {$name} is not supported"
            );
        }

        $method = "create" . ucfirst(self::$supportedAdapters[$name]) . "Adapter";

        return $this->{$method}();
    }

    public function createPaystackAdapter()
    {
        return $this->app->make("gbowo.paystack");
    }

    public function createAmplifyPayAdapter()
    {
        return $this->app->make("gbowo.amplifypay");
    }

    public function extend(string $adapterName, Closure $callback)
    {
        $this->customAdapters[$adapterName] = $callback;
    }
}

And of course,the facade

<?php

namespace Gbowo\Bridge\Laravel\Facades;

use Illuminate\Support\Facades\Facade;

class Gbowo extends Facade
{
    protected static function getFacadeAccessor()
    {
        return 'gbowo';
    }
}

As i said earlier, I wanted to be certain i was interacting correctly with Laravel ?. So how do i get that done ? There are actually two ways to do this :

The first option is exactly the same reason i didn’t have a testsuite for the bridge while it lived in the core library. Well, another reason was because i didn’t want to have to specify laravel/framework as a dependency - require or require --dev. So i skipped this.

The second option makes a lot of sense since we have avoid all that bootstrapping and use only the part of the framework we need to communicate with. I ended up going with this option and is what would be described iin this post.

If the concepts of mocking are somewhat new to you, i wrote a primer on that, you might want to check that.

Since the GbowoManager makes use of the Application instance Laravel has to provide with all services already bounded and isn’t too coupled to Laravel, that seems like a nice place to start.

<?php

namespace Gbowo\Bridge\Laravel\Tests;

use InvalidArgumentException;
use Gbowo\Adapter\Amplifypay\AmplifypayAdapter;
use Gbowo\Adapter\Paystack\PaystackAdapter;
use Gbowo\Bridge\Laravel\GbowoManager;
use Gbowo\Contract\Adapter\AdapterInterface;
use Gbowo\GbowoFactory;
use Illuminate\Config\Repository;
use Illuminate\Foundation\Application;
use PHPUnit\Framework\TestCase;
use Prophecy\Argument;
use Prophecy\Prophet;

class GbowoManagerTest extends TestCase
{

    protected $manager;

    protected $prophet;

    public function tearDown()
    {
        $this->prophet->checkPredictions();
    }

    public function setUp()
    {
        $this->prophet = new Prophet();

        $app = $this->prophet->prophesize(Application::class);

        $app->offsetGet("config")
            ->willReturn(new Repository(["services" => ["gbowo" => ["default" => "paystack"]]]));

        $app->make("gbowo.paystack")
            ->willReturn(new PaystackAdapter());

        $app->make("gbowo.amplifypay")
            ->willReturn(new AmplifypayAdapter());

        $this->manager = new GbowoManager($app->reveal());
    }

}

Prophet is a mocking framework that comes with PHPUnit. Mockery can also be used.

The most interesting parts are

<?php

        $app->offsetGet("config")
            ->willReturn(new Repository(["services" => ["gbowo" => ["default" => "paystack"]]]));

        $app->make("gbowo.paystack")
            ->willReturn(new PaystackAdapter());

        $app->make("gbowo.amplifypay")
            ->willReturn(new AmplifypayAdapter());

We created a mock that can act as a replacement with prophesize(Application::class)after which we added some stubs to it.

We are faking that we have gbowo.amplifypay and gbowo.paystack as registered services in the container when we actually don’t. Same thing goes for config. This is because we aren’t bootstrapping the framework, hence we don’t get a real Laravel Application instance. Meaning we have to act as if it was a real Laravel instance running.

Great ? How about making sure that works ?

<?php 

class GbowoManagerTest extends TestCase
{

   //previous code


    public function testDefaultDriverNameIsCorrectlyDetermined()
    {
    	//This test is just to make sure the method returns what is expected.
    	//Hack ???
        $method = new \ReflectionMethod($this->manager, "getDefaultDriverName");
        $method->setAccessible(true);

        $this->assertSame(GbowoFactory::PAYSTACK, $method->invoke($this->manager));
    }   


    /**
     * @dataProvider adapters
     */
    public function testAdapter(string $adapterName, string $adapter)
    {
        $this->assertInstanceOf($adapter, $this->manager->adapter($adapterName));
    }

    public function adapters()
    {
        return [
            [GbowoFactory::PAYSTACK, PaystackAdapter::class],
            [GbowoFactory::AMPLIFY_PAY, AmplifypayAdapter::class]
        ];
    }

}

Running that should give us green but we still have a huge part of the manager that isn’t tested yet. It allows for extensibility and we haven’t tested that yet. It throws exceptions when it couldn’t resolve an adapter by a name. Let’s put those in our test.

<?php

class GbowoManagerTest extends TestCase
{
    //previous code


    public function testFetchesTheDefaultAdapterImplementation()
    {
        //The setup method defines the default adapter as "paystack", so we expect the paystack adapter
        $this->assertInstanceOf(PaystackAdapter::class, $this->manager->adapter());
    }

    public function testUnableToResolveUnknownAdapter()
    {
        $this->expectException(InvalidArgumentException::class);

        $this->manager->adapter("interswitch");
    }

    public function testExtensibility()
    {
        $stripeAdapter = new class implements AdapterInterface
        {
            const ADAPTER_NAME = "stripe";

            public function charge(array $data = [])
            {
                return "Charged by " . ucfirst(self::ADAPTER_NAME);
            }
        };

        $this->manager->extend(
            "stripe",
            function () use ($stripeAdapter) {
                return $stripeAdapter;
            });

        $this->assertSame($stripeAdapter, $this->manager->adapter("stripe"));
    }

    public function testPaystackAdapter()
    {
        $this->assertInstanceOf(
            PaystackAdapter::class,
            $this->manager->createPaystackAdapter()
        );
    }

    public function testAmplifyPayAdapter()
    {
        $this->assertInstanceOf(
            AmplifypayAdapter::class,
            $this->manager->createAmplifyPayAdapter()
        );
    }

}

With the above tests, we are certain that the Manager would work as expected if it gets into a real Laravel application. And that is the type of confidence i like to have with my codebase.

While this is enough to build confidence that the package works as expected since the Facade and ServiceProvider are heavily dependent on Laravel - and their workings are actually implemented in Laravel. We can push the tests a bit harder by testing the Facade.

We can decide to leave this out as the Manager tests already confirms our trust in the package doing it’s thing

<?php

namespace Gbowo\Bridge\Laravel\Tests;

use Gbowo\Bridge\Laravel\Facades\Gbowo;
use Gbowo\Bridge\Laravel\GbowoManager;
use Illuminate\Foundation\Application;
use PHPUnit\Framework\TestCase;

class GbowoTest extends TestCase
{

    public function setUp()
    {
        $app = $this->prophesize(Application::class);

        $app->offsetGet("gbowo")
            ->willReturn(new GbowoManager($app->reveal()));

        Gbowo::setFacadeApplication($app->reveal());
    }

    public function testFacadesWorksAsExpected()
    {
        $this->assertInstanceOf(
            GbowoManager::class,
            Gbowo::getFacadeRoot()
        );
    }
}

Here, we are eseentially making sure the Facade resolves to the GbowoManager. The message passing is done by Laravel, so we can leave that out trusting Laravel to work as expected.

As said alone, i am not interested in testing the service provider as that is too Laravel tied and even if i do, it would have ended up as a useless test and i don’t feel the need to get to a 100% coverage.

You can have a look at the tests on github

Hopefully this helps someone.

Footnotes

[0] I understand code coverage doesn’t imply quality