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

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

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 

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 

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 

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 

FEEDBACK 

RELIABILITY 

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

INVERTED TEST PYRAMID Unit Service UI 

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

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 

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

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 

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 

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 

Doctrine Manager Guzzle Client DB HTTP Unit tests Integration tests PriceCalculator 

UNIT TESTING THE PRICE CALCULATOR PriceCalculator Guzzle Client interface ProductRepository
 {
 /**
 * @param string $uuid
 *
 * @return Product
 *
 * @throws ProductNotFoundException
 */
 public function findOneByUuid($uuid);
 } ProductRepository 

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 

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 

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 

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 

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 

Doctrine Manager Guzzle Client DB HTTP Unit tests Integration tests PriceCalculator 

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

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 

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 

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

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 

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 

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 

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 

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

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

PriceCalculator CurrencyConverter ProductRepository AcmeApiCurrencyConverter AcmeApi DoctrineProductRepository GuzzleCurrencyConverter Doctrine Manager Guzzle Client 

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

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