tdd-codecamp

Step by step reference for the hands on session during the June 16, 2018 TDD codecamp.

Getting Started

These instructions will get you a copy of the project up and running on your local machine. See commits section for reference to the actual code changes made at each step.

Prerequisites

• Laravel 5.6

Instructions

Step by step documentation of the afternoon tdd hands on session.

Steps

1. Let's begin by creating a new Laravel application. Open your terminal, navigate to your development directory and execute the following command

laravel new ticketbeast

2. Next we need to make our test file. This can be achieve using the following command

php artisan make:test PurchaseTicketsTest

3. Time to create our test case! Open the file app/tests/Feature/PurchaseTicketsTest.php and locate the following code

/**
 * A basic test example.
 *
 * @return void
 */
public function testExample()
{
    $this->assertTrue(true);
}

Replace it with this bit

/** @test */
public function customer_can_purchase_tickets()
{
	
    // Arrange
    
    // Act
    
    // Assert
}

Save the changes and run the test using the following command

./vendor/bin/phpunit --filter=customer_can_purchase_tickets

Which will give you the following result

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
This test did not perform any assertions

OK, but incomplete, skipped, or risky tests!
Tests: 1, Assertions: 0, Risky: 1.

NOTE: The filter option indicates that only the given test case will be executed

4. Lets add a couple more lines to reflect the general idea of how the test case should look like

/** @test */
public function customer_can_purchase_tickets()
{
    // Arrange
    $concert = factory(Concert::class)->create();

    // Act
    $response = $this->post("concerts/{$concert->id}/orders", []);

    // Assert
    $response->assertStatus(201);
}

Save the changes and run the test again. Please note that we will be using the same command to run the test unless specified otherwise.

./vendor/bin/phpunit --filter=customer_can_purchase_tickets

At this point you should be seeing the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Error: Class 'Tests\Feature\Concert' not found

TIP: Use the up arrow key to cycle thru your previously executed commands instead of typing or copy/paste to save time.

5. Create the Concert model by executing the following command

php artisan make:model Concert

You will find out after running the test that we are still getting the same error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Error: Class 'Tests\Feature\Concert' not found

Let's fix that by updating the following code

namespace Tests\Feature;

use Tests\TestCase;
use Illuminate\Foundation\Testing\WithFaker;
use Illuminate\Foundation\Testing\RefreshDatabase;

class PurchaseTicketsTest extends TestCase

By aliasing our newly created Concert model

namespace Tests\Feature;

use App\Concert;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Tests\TestCase;

class PurchaseTicketsTest extends TestCase

Running the test again will now result to

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
InvalidArgumentException: Unable to locate factory with name [default] [App\Concert].

6. Create a concert factory by executing the following command

php artisan make:factory ConcertFactory --model="App\Concert"

Run the test and arrive at the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Illuminate\Database\QueryException: SQLSTATE[HY000] [1045] Access denied for user 'homestead'@'localhost' (using password: YES) (SQL: insert into `concerts` (`updated_at`, `created_at`) values (2018-06-17 09:05:06, 2018-06-17 09:05:06))

7. Open the file ticketbeast\phpunit.xml and locate the following code

<php>
    <env name="APP_ENV" value="testing"/>
    <env name="BCRYPT_ROUNDS" value="4"/>
    <env name="CACHE_DRIVER" value="array"/>
    <env name="SESSION_DRIVER" value="array"/>
    <env name="QUEUE_DRIVER" value="sync"/>
    <env name="MAIL_DRIVER" value="array"/>
</php>

Update it to

<php>
    <env name="APP_ENV" value="testing"/>
    <env name="BCRYPT_ROUNDS" value="4"/>
    <env name="CACHE_DRIVER" value="array"/>
    <env name="SESSION_DRIVER" value="array"/>
    <env name="QUEUE_DRIVER" value="sync"/>
    <env name="MAIL_DRIVER" value="array"/>
    <env name="DB_CONNECTION" value="sqlite"/>
    <env name="DB_DATABASE" value=":memory:"/>
</php>

Save the changes and run the test again. This will now result to the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Illuminate\Database\QueryException: SQLSTATE[HY000]: General error: 1 no such table: concerts (SQL: insert into "concerts" ("updated_at", "created_at") values (2018-06-17 09:18:25, 2018-06-17 09:18:25))

8. Create a migration file by executing the following command

php artisan make:migration create_concerts_table --create=concerts

Running the test again however will result to the same error

Locate the following code in PurchaseTicketsTest.php

class PurchaseTicketsTest extends TestCase
{
    /** @test */
    public function customer_can_purchase_tickets()
    {

And let's update it to

class PurchaseTicketsTest extends TestCase
{
	use DatabaseMigrations;

	/** @test */
    public function customer_can_purchase_tickets()
    {

NOTE: Adding this line will simply run the migration files automatically everytime the test is run

Running the test will now give us the following error

PHP Fatal error:  Trait 'Tests\Feature\DatabaseMigrations' not found in /ticketbeast/tests/Feature/PurchaseTicketsTest.php on line 12

Go back to PurchaseTicketsTest.php and locate the following code

use App\Concert;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Tests\TestCase;

Update it to the following code, save and run the test again

use App\Concert;
use Illuminate\Foundation\Testing\DatabaseMigrations;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Tests\TestCase;

It should now give us the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Expected status code 201 but received 404.
Failed asserting that false is true.

9. Create controller which will handle all concert ticket order requests by executing the following command

php artisan make:controller ConcertOrderController --model="App\Concert" --api

Open the file ticketbeast/Http/Controllers/ConcertOrderController.php and locate the following code

public function store(Request $request)
{
    //
}

Let's update it to the following for now

public function store(Request $request)
{
    return response()->json([], 201);
}

Save the changes and run the test. This will still result to the same error.

Open ticketbeast/routes/web.php and append the following code

Route::post('concerts/{concert}/orders', 'ConcertOrderController@store');

Run the test again and BOOM! Our first green light! 💪 (technically!)

PHPUnit 7.2.4 by Sebastian Bergmann and contributors.

.                                                                   1 / 1 (100%)

Time: 157 ms, Memory: 16.00MB

10. Next, let's update our customer_can_purchase_tickets to the following code

	public function customer_can_purchase_tickets()
    {
        // Arrange
        $concert = factory(Concert::class)->create([
        	'ticket_price' => 3250
        ]);

        // Act
        $response = $this->post("concerts/{$concert->id}/orders", [
        	'email' 			=> 'john@example.com',
            'ticket_quantity' 	=> 3,
            'payment_gateway' 	=> $paymentGateway->getValidTestToken()
        ]);

        // Assert
        $response->assertStatus(201);

        $this->assertEquals(9750, $paymentGateway->totalCharges());
    }

**NOTE: total charges = ticket price x ticket quantity = 3250 x 3 = 9750 **

Running the test will now give us the error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Illuminate\Database\QueryException: SQLSTATE[HY000]: General error: 1 table concerts has no column named ticket_price (SQL: insert into "concerts" ("ticket_price", "updated_at", "created_at") values (3250, 2018-06-17 10:18:09, 2018-06-17 10:18:09))

11. Open the create_concerts_table migration file and locate the following code

NOTE: Exact file names will be prefixed differently, _<prefix>create_concerts_table.php

Schema::create('concerts', function (Blueprint $table) {
    $table->increments('id');
    $table->timestamps();
});

Add a column for ticket price, save and run the test

Schema::create('concerts', function (Blueprint $table) {
    $table->increments('id');
    $table->integer('ticket_price');
    $table->timestamps();
});

At this point you should be seeing the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
ErrorException: Undefined variable: paymentGateway

12. Create a folder app/Billing and create a file FakePaymentGateway.php under it

Open and update it's contents to

<?php

namespace App\Billing;

class FakePaymentGateway
{

}

Now let's go over to PurchaseTicketsTest.php and add the following code

$paymentGateway = new FakePaymentGateway();

So that it now looks like this

// Arrange
$paymentGateway = new FakePaymentGateway();
$concert = factory(Concert::class)->create([
    'ticket_price' => 3250
]);

After running the test again, the error should have now changed to

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Error: Class 'Tests\Feature\FakePaymentGateway' not found

Fixing the reference should be easy enough, like this

use App\Billing\FakePaymentGateway;
use App\Concert;
use Illuminate\Foundation\Testing\DatabaseMigrations;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Tests\TestCase;

Save, run the test and now we got ourselves a different error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Error: Call to undefined method App\Billing\FakePaymentGateway::getValidTestToken()

Let's add the following method to FakePaymentGateway.php

public function getValidTestToken()
{
    return 'valid-token';
}

Save and run again to arrive at the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Error: Call to undefined method App\Billing\FakePaymentGateway::totalCharges()

This time let's update FakePaymentGateway.php so that it now looks like this

class FakePaymentGateway
{
    protected $charges;

    public function __construct()
    {
        $this->charges = collect();
    }

    public function getValidTestToken()
    {
        return 'valid-token';
    }

    public function totalCharges()
    {
        return $this->charges->sum();
    }
}

NOTE: Please refer to the official documentation for collect

At this point the error should now be

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Failed asserting that 0 matches expected 9750.

13. Head over to ConcertOrderController.php and update the store method to

public function store(Request $request, $concertId)
{
    $paymentGateway = new FakePaymentGateway();
    $concert = Concert::find($concertId);

    $amount = $concert->ticket_price * $request->get('ticket_quantity');
    $paymentGateway->charge($amount, $request->get('payment_gateway'));

    return response()->json([], 201);
}

Running the test will now result to

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Expected status code 201 but received 500.
Failed asserting that false is true.

Which isn't very helpful so let's open app\Exceptions\Handler.php, find and update the report method to

public function report(Exception $exception)
{
    throw $exception;
    parent::report($exception);
}

NOTE: During the actual hands on session, the report method was updated somewhere between step 8 and 9.

If we run the test again it will now give us

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Symfony\Component\Debug\Exception\FatalThrowableError: Class 'App\Http\Controllers\FakePaymentGateway' not found

Ah, much better. Do remember to remove the throw before you publish your code, it is meant for debugging only!

Let's go ahead and add a reference to FakePaymentGateway

use App\Billing\FakePaymentGateway;
use App\Concert;
use Illuminate\Http\Request;

class ConcertOrderController extends Controller

Once we have that the error should now be

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Symfony\Component\Debug\Exception\FatalThrowableError: Call to undefined method App\Billing\FakePaymentGateway::charge()

Go ahead and define that method

public function charge($amount, $token)
{
    $this->charges->push($amount);
}

Save and run the test so the result will now be

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Failed asserting that 0 matches expected 9750.

14. Let's recap At the end of step 12 we had the following error

1) Tests\Feature\PurchaseTicketsTest::customer_can_purchase_tickets
Failed asserting that 0 matches expected 9750.

During step 13 we added the charge logic which is

total charges = ticket price x ticket quantity

However we still arrived on the same error before at the beginning of step 13!

Why?

Remember this from PurchaseTicketsTest.php?

$paymentGateway = new FakePaymentGateway();

We can see here that a new fake payment gateway is being initialized

Moving along the customer_can_purchase_tickets method you will see

$response = $this->post("concerts/{$concert->id}/orders", [
    'email'             => 'john@example.com',
    'ticket_quantity'   => 3,
    'payment_gateway'   => $paymentGateway->getValidTestToken()
]);

Which calls the store method in ConcertOrderController.php and a new fake payment gateway is being initialized

$paymentGateway = new FakePaymentGateway();

Even thou we added the charge logic and invoke the fake payment gateway charge method and seen below

$amount = $concert->ticket_price * $request->get('ticket_quantity');
$paymentGateway->charge($amount, $request->get('payment_gateway'));

Because $paymentGateway in PurchaseTicketsTest.php is a different instance of FakePaymentGateway from that of $paymentGateway in ConcertOrderController.php it will not be able to receive the changes that have been made when the charge method was invoked in ConcertOrderController.php.

To resolve this we need to modify the FakePaymentGateway so it implements the Singleton design pattern, ergo it will return the same exact instance everytime it is initialized.

Let's get started.

Create a file named PaymentGateway.php under ticketbeast\app\Billing and with the following content

<?php

namespace App\Billing;

interface PaymentGateway
{
    public function charge($amount, $token);
}

Update FakePaymentGateway so that it now looks like this

class FakePaymentGateway implements PaymentGateway

Next update ConcertOrderController.php to

use App\Billing\FakePaymentGateway;
use App\Billing\PaymentGateway;
use App\Concert;
use Illuminate\Http\Request;

class ConcertOrderController extends Controller
{
    protected $paymentGateway;

    public function __construct(PaymentGateway $paymentGateway)
    {
        $this->paymentGateway = $paymentGateway;
    }

And the store method to

public function store(Request $request, $concertId)
{
    $concert = Concert::find($concertId);

    $amount = $concert->ticket_price * $request->get('ticket_quantity');
    $this->paymentGateway->charge($amount, $request->get('payment_gateway'));

    return response()->json([], 201);
}

Next we will update PurchaseTicketsTest.php to

use App\Billing\FakePaymentGateway;
use App\Concert;
use Illuminate\Foundation\Testing\DatabaseMigrations;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Tests\TestCase;

class PurchaseTicketsTest extends TestCase

And customer_can_purchase_tickets to

public function customer_can_purchase_tickets()
{
    // Arrange
    $paymentGateway = new FakePaymentGateway();
    $this->app->instance(PaymentGateway::class, $paymentGateway);
    
    $concert = factory(Concert::class)->create([
        'ticket_price' => 3250
    ]);

If we run the test again, we should have arrive at a green light with a message similar or equal to

PHPUnit 7.2.4 by Sebastian Bergmann and contributors.

.                                                                   1 / 1 (100%)

Time: 149 ms, Memory: 16.00MB

OK (1 test, 2 assertions)

Authors

• Harlequin Doyon - Resource Speaker - harlekoy
• Laravel Cebu - Event organizers - laravelcebu
• Ian Panara - Documentation - fatcodingbastard

See also the list of contributors who participated in this project.

License

This project is licensed under the MIT License - see the LICENSE.md file for details

Acknowledgments

• Hat tip to anyone whose code was used
• Sponsors
• Event Organizers
• Resource speakers
• etc