Lightning fast Symfony tests

One of the benefits of having an automated test suite is the feedback given when the code is being changed. As a project grows, the test suite becomes slower and slower every day, until it’s so slow it stops being useful.

Learn how to structure your Symfony project to benefit from lightning fast tests. Apply the right amount of testing on appropriate levels, and run your tests in seconds, not hours.

Transcript

1. LIGHTNING FAST SYMFONY TESTS
   Jakub Zalas
   https://www.flickr.com/photos/captainkimo/7934118876/
   @jakub_zalas
   @jakzal
   

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2. WHAT MAKES TESTS SLOW?
   https://www.flickr.com/photos/davemedia/6158362891/
   

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3. Selenium
   Web server
   + PHP
   Symfony
   WebDriverTest
   DB API
   MyCode
   Controller
   Service A
   Service B
   GoutteTest
   BrowserKitTest
   ServiceTest
   TYPES OF AUTOMATED TESTS
   ➤ Integration
   ➤ UI
   ➤ Service
   ➤ Acceptance
   ➤ Unit
   

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4. if ($serviceA->isEnabled()) {

   $serviceB->callFoo();

   } else {

   $serviceB->callBar();

   }

   

   if ($serviceA->has('foo') && $serviceA->has('bar')) {

   $serviceB->callBaz();

   }
   COUNT EXECUTION PATHS
   2
   4
   2 x 4 = 8
   

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5. EXECUTION PATHS IN AN INTEGRATION TEST
   MyCode
   Controller
   Repository
   Service A
   Service B
   4
   2
   5
   2
   4 x 2 x 5 x 2 = 80
   

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6. EXECUTION PATHS IN AN INTEGRATION TEST
   MyCode
   Controller
   Repository
   Service A
   Service B
   4
   2
   2
   2
   4 x 2 x 5 x 2 = 80
   Service C
   3
   4 x 2 x 2 x 3 x 2 = 96
   

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7. FEEDBACK
   

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8. RELIABILITY
   

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9. TEST PYRAMID
   Unit
   Service
   UI
   Succeeding with Agile: Software Development Using Scrum, Mike Cohn
   

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10. INVERTED TEST PYRAMID
    Unit
    Service
    UI
    

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11. TESTING ICE-CREAM CONE
    Unit
    Service
    UI
    Manual tests
    http://watirmelon.com/2012/01/31/introducing-the-software-testing-ice-cream-cone/
    

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12. SPEED’S NOT THE ONLY ISSUE
    https://www.flickr.com/photos/hsing/3580898648/
    Unit Integration
    Fast Slow
    Reliable Brittle
    Good feedback Poor feedback
    Grow linearly Grow exponentially
    Force better design Put pressure off the design
    Isolated Can simulate user journeys
    

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13. UNIT TESTING
    https://www.flickr.com/photos/ghozttramp/15390041831/
    

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14. IMPLEMENTING A PRICE CALCULATOR
    ➤ A small service to calculate a product price in chosen currency
    ➤ Products are stored in a database
    ➤ Currency converter is provided as a third party API
    

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15. THE OBVIOUS IMPLEMENTATION
    PriceCalculator
    Guzzle Client
    use Doctrine\ORM\EntityManager;

    use GuzzleHttp\Client;

    

    final class PriceCalculator

    {

    /**

    * @var EntityManager

    */

    private $em;

    

    /**

    * @var Client

    */

    private $guzzle;

    

    public function __construct(EntityManager $em, Client $guzzle)

    {

    $this->em = $em;

    $this->guzzle = $guzzle;

    }

    

    public function price($productUuid, Currency $targetCurrency)

    {

    }

    }
    Doctrine EntityManager
    

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16. PriceCalculator
    Guzzle Client
    public function price($productUuid, Currency $targetCurrency)

    {

    $products = $this->em->getRepository(Product::class);

    $product = $products->findOneByUuid($productUuid);

    

    if (!$product) {

    throw new ProductNotFoundException();

    }

    

    if ($product->isOutOfStock()) {

    throw new OutOfStockException();

    }

    

    if ($product->isPriceInCurrency($targetCurrency)) {

    return $product->getPrice();

    }

    

    $price = $product->getPrice();

    $query = http_build_query([

    'amount' => $price->getAmount(),

    'from_currency' => $price->getCurrencyCode(),

    'to_currency' => $targetCurrency->getCode(),

    ]);

    $response = $this->guzzle->get('/convert?'.$query);

    

    $price = json_decode($response->getBody());

    

    return new Price($price->amount, $targetCurrency);

    }
    Doctrine EntityManager
    THE OBVIOUS IMPLEMENTATION
    

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17. Doctrine Manager Guzzle Client
    DB HTTP
    Unit tests
    Integration
    tests
    PriceCalculator
    

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18. UNIT TESTING THE PRICE CALCULATOR
    PriceCalculator
    Guzzle Client
    interface ProductRepository

    {

    /**

    * @param string $uuid

    *

    * @return Product

    *

    * @throws ProductNotFoundException

    */

    public function findOneByUuid($uuid);

    }
    ProductRepository
    

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19. UNIT TESTING THE PRICE CALCULATOR
    PriceCalculator
    CurrencyConverter
    interface CurrencyConverter

    {

    /**

    * @param Price $price

    * @param Currency $targetCurrency

    *

    * @return Currency

    */

    public function convert(Price $price, Currency $targetCurrency);

    }
    ProductRepository
    

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20. UNIT TESTING THE PRICE CALCULATOR
    PriceCalculator
    CurrencyConverter
    class PriceCalculatorTest extends \PHPUnit_Framework_TestCase

    {

    const UUID = 'foo-u-u-i-d';

    

    public function test_it_converts_price_to_the_target_currency()

    {

    $price = new Price(200, new Currency('GBP'));

    $product = new TestProduct($price);

    $expectedPrice = new Price(277, new Currency('EUR'));

    

    $productRepository = $this->prophesize(ProductRepository::class);

    $productRepository->findOneByUuid(self::UUID)

    ->willReturn($product);

    

    $currencyConverter = $this->prophesize(CurrencyConverter::class);

    $currencyConverter->convert($price, new Currency('EUR'))

    ->willReturn($expectedPrice);

    

    $priceCalculator = new PriceCalculator(

    $productRepository->reveal(),

    $currencyConverter->reveal()

    );

    $price = $priceCalculator->price(self::UUID, new Currency('EUR'));
    

    $this->assertSame($expectedPrice, $price);

    }

    }
    ProductRepository
    

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21. UNIT TESTING THE PRICE CALCULATOR
    PriceCalculator
    CurrencyConverter
    final class PriceCalculator

    {

    /**

    * @var ProductRepository

    */

    private $products;

    

    /**

    * @var CurrencyConverter

    */

    private $converter;

    

    public function __construct(

    ProductRepository $products,

    CurrencyConverter $converter

    ) {

    $this->products = $products;

    $this->converter = $converter;

    }

    

    public function price($productUuid, Currency $targetCurrency)

    {

    $product = $this->products->findOneByUuid($productUuid);

    

    return $this->converter->convert(

    $product->getPrice(),

    $targetCurrency

    );

    }

    }
    ProductRepository
    

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22. UNIT TESTING THE PRICE CALCULATOR
    PriceCalculator
    CurrencyConverter
    /**

    * @expectedException OutOfStockException

    */

    public function test_it_throws_an_exception_if_product_is_out_of_stock()
    {

    $product = new OutOfStockProduct(

    new Price(200, new Currency('GBP'))

    );

    

    $productRepository = $this->prophesize(ProductRepository::class);

    $productRepository->findOneByUuid(self::UUID)

    ->willReturn($product);

    

    $currencyConverter = $this->prophesize(CurrencyConverter::class);

    

    $priceCalculator = new PriceCalculator(

    $productRepository->reveal(),

    $currencyConverter->reveal()

    );

    $priceCalculator->price(self::UUID, new Currency('EUR'));

    }
    ProductRepository
    

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23. UNIT TESTING THE PRICE CALCULATOR
    PriceCalculator
    CurrencyConverter
    final class PriceCalculator

    {

    // ...

    

    public function price($productUuid, Currency $targetCurrency)

    {

    $product = $this->products->findOneByUuid($productUuid);

    

    if ($product->isOutOfStock()) {

    throw new OutOfStockException($product);

    }

    

    return $this->converter->convert(

    $product->getPrice(),

    $targetCurrency

    );

    }

    }
    ProductRepository
    

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24. Doctrine Manager Guzzle Client
    DB HTTP
    Unit tests
    Integration
    tests
    PriceCalculator
    

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25. Doctrine Manager Guzzle Client
    DB HTTP
    Unit tests
    Integration
    tests
    CurrencyConverter
    ProductRepository
    DoctrineProductRepository GuzzleCurrencyConverter
    PriceCalculator
    

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26. INTEGRATION TESTING THE REPOSITORY
    PriceCalculator
    CurrencyConverter
    class DoctrineProductRepositoryTest extends \PHPUnit_Framework_TestCase

    {

    protected function setUp()

    {

    // set up the database with fixtures

    }

    

    public function test_it_returns_a_product_by_its_uuid()

    {

    $repository = new DoctrineProductRepository(

    $this->createEntityManager()

    );

    

    $product = $repository->findByUuid('known-u-u-i-d');

    

    $this->assertInstanceOf(Product::class, $product);

    }

    

    /**

    * @expectedException ProductNotFound

    */

    public function test_it_throws_an_exception_if_product_is_not_found(
    {

    $repository = new DoctrineProductRepository(

    $this->createEntityManager()

    );

    

    $repository->findByUuid('unknown-u-u-i-d');

    }

    }
    ProductRepository
    DoctrineProductRepository
    

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27. TWO SIDES OF THE CONTRACT
    ➤ An interface is a contract
    ➤ User of the interface makes assumptions
    about its behaviour in unit tests with test
    doubles
    ➤ The implementor of the interface needs
    to prove it implements the contract
    properly (test double assumptions are
    true)
    ➤ For each expectation in the unit test there
    should be at least one test to verify that
    expectation
    PriceCalculator
    CurrencyConverter
    ProductRepository
    DoctrineProductRepository
    

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28. Doctrine Manager Guzzle Client
    DB HTTP
    Unit tests
    Integration
    tests
    CurrencyConverter
    ProductRepository
    DoctrineProductRepository GuzzleCurrencyConverter
    PriceCalculator
    

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29. UNIT TESTING THE CURRENCY CONVERTER
    PriceCalculator
    CurrencyConverter interface AcmeApi

    {

    /**

    * @param int $price

    * @param string $fromCurrency

    * @param string $toCurrency

    *

    * @return int

    */

    public function convert($price, $fromCurrency, $toCurrency);

    }
    ProductRepository
    DoctrineProductRepository AcmeApiCurrencyConverter
    GuzzleCurrencyConverter
    AcmeApi
    

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30. UNIT TESTING THE CURRENCY CONVERTER
    PriceCalculator
    CurrencyConverter
    class AcmeApiCurrencyConverterTest extends \PHPUnit_Framework_TestCase

    {

    public function test_it_returns_the_original_price_if_no_conversion_
    {

    $price = new Price(200, new Currency('GBP'));

    $targetCurrency = new Currency('GBP');

    

    $acmeApi = $this->prophesize(AcmeApi::class);

    

    $converter = new AcmeApiCurrencyConverter($acmeApi);

    $actualPrice = $converter->convert($price, $targetCurrency);

    

    $this->assertSame($price, $actualPrice);

    }

    

    public function test_it_calls_the_api_to_convert_the_currency()

    {

    $price = new Price(200, new Currency('GBP'));

    $targetCurrency = new Currency('GBP');

    

    $acmeApi = $this->prophesize(AcmeApi::class);

    $acmeApi->convert(200, 'GBP', 'EUR')->willReturn(277);

    

    $converter = new AcmeApiCurrencyConverter($acmeApi);

    $actualPrice = $converter->convert($price, $targetCurrency);

    

    $this->assertEquals(new Price(277, 'EUR'), $actualPrice);

    }

    }
    ProductRepository
    DoctrineProductRepository AcmeApiCurrencyConverter
    GuzzleCurrencyConverter
    AcmeApi
    

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31. INTEGRATION TESTING THE CURRENCY CONVERTER
    PriceCalculator
    CurrencyConverter
    use GuzzleHttp\Client;

    

    class GuzzleAcmeApiTest extends \PHPUnit_Framework_TestCase

    {

    public function test_it_converts_the_price()

    {

    $acmeApi = new GuzzleAcmeApi(new Client());

    

    $amount = $acmeApi->convert(200, 'GBP', 'EUR');

    

    $this->assertInternalType('int', $amount);

    }

    }
    ProductRepository
    DoctrineProductRepository AcmeApiCurrencyConverter
    GuzzleCurrencyConverter
    AcmeApi
    

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32. INTEGRATION TESTING THE CURRENCY CONVERTER
    PriceCalculator
    CurrencyConverter
    use GuzzleHttp\Client;

    

    final class GuzzleAcmeApi implements AcmeApi

    {

    /**

    * @var Client

    */

    private $guzzle;

    

    public function __construct(Client $guzzle)

    {

    $this->guzzle = $guzzle;

    }

    

    public function convert($price, $fromCurrency, $toCurrency)

    {

    $query = http_build_query([

    'amount' => $price,

    'from_currency' => $fromCurrency,

    'to_currency' => $toCurrency,

    ]);

    $response = $this->guzzle->get('/convert?'.$query);

    

    $price = json_decode($response->getBody());

    

    return (int) $price->amount;

    }

    }
    ProductRepository
    DoctrineProductRepository AcmeApiCurrencyConverter
    GuzzleCurrencyConverter
    AcmeApi
    

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33. Doctrine Manager Guzzle Client
    DB HTTP
    Unit tests
    Integration
    tests
    CurrencyConverter
    ProductRepository
    DoctrineProductRepository GuzzleCurrencyConverter
    PriceCalculator
    

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34. Doctrine Manager Guzzle Client
    DB HTTP
    Unit tests
    Integration
    tests
    CurrencyConverter
    ProductRepository
    DoctrineProductRepository GuzzleCurrencyConverter
    PriceCalculator
    AcmeApiCurrencyConverter
    AcmeApi
    

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35. PriceCalculator CurrencyConverter
    ProductRepository AcmeApiCurrencyConverter
    AcmeApi
    DoctrineProductRepository
    GuzzleCurrencyConverter
    Doctrine Manager
    Guzzle Client
    

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36. PriceCalculator CurrencyConverter
    ProductRepository AcmeApiCurrencyConverter
    AcmeApi
    DoctrineProductRepository
    GuzzleCurrencyConverter
    Doctrine Manager
    Guzzle Client
    InMemoryRepository
    PriceCalculatorController
    Symfony
    BehatContext
    Behat
    

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37. @jakub_zalas @jakzal
    Thank you.
    Rate my talk, please:
    https://joind.in/16482
    

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