Testing Legacy Troubles

Transcript

1. TESTING LEGACY TROUBLES @konrad_126
2. LEGACY CODE? NO TESTS.
3. THE CASE OF AN IRRITATING PARAMETER
4. <?php class CalculatePrice { public function __construct(private VatDotComClient $vatProvider) { } public function calculate(Product $product) : float { $taxRate = $this->vatProvider->getRate($product->countryCode()); // some business logic to calculate price } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 public function __construct(private VatDotComClient $vatProvider) <?php 1 2 class CalculatePrice 3 { 4 5 { 6 } 7 8 public function calculate(Product $product) : float 9 { 10 $taxRate = $this->vatProvider->getRate($product->countryCode()); 11 // some business logic to calculate price 12 } 13 } 14 $taxRate = $this->vatProvider->getRate($product->countryCode()); <?php 1 2 class CalculatePrice 3 { 4 public function __construct(private VatDotComClient $vatProvider) 5 { 6 } 7 8 public function calculate(Product $product) : float 9 { 10 11 // some business logic to calculate price 12 } 13 } 14 // some business logic to calculate price <?php 1 2 class CalculatePrice 3 { 4 public function __construct(private VatDotComClient $vatProvider) 5 { 6 } 7 8 public function calculate(Product $product) : float 9 { 10 $taxRate = $this->vatProvider->getRate($product->countryCode()); 11 12 } 13 } 14
5. <?php class CalculatePriceTest { public function itAppliesTheTaxRate() { $calculateTax = new CalculatePrice( new VatDotComClient('api-key', 'secret') ); // ... } } 1 2 3 4 5 6 7 8 9 10 11 12 $calculateTax = new CalculatePrice( <?php 1 2 class CalculatePriceTest 3 { 4 public function itAppliesTheTaxRate() 5 { 6 7 new VatDotComClient('api-key', 'secret') 8 ); 9 // ... 10 } 11 } 12 new VatDotComClient('api-key', 'secret') <?php 1 2 class CalculatePriceTest 3 { 4 public function itAppliesTheTaxRate() 5 { 6 $calculateTax = new CalculatePrice( 7 8 ); 9 // ... 10 } 11 } 12
6. <?php class CalculatePriceTest { public function itAppliesTheTaxRate() { // ... } public function itAppliesDiscount() { // ... } public function itAppliesVoucher() { // ... } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 vat.com
7. <?php class CalculatePriceTest { public function itAppliesTheTaxRate() { // ... } public function itAppliesDiscount() { // ... } public function itAppliesVoucher() { // ... } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 dummy VAT provider
8. <?php class CalculatePrice { public function __construct(private VatDotComClient $vatProvider) { } public function calculate(Product $product) { $taxRate = $this->vatProvider->getRate($product->countryCode()); // some business logic to calculate price } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 public function __construct(private VatDotComClient $vatProvider) <?php 1 2 class CalculatePrice 3 { 4 5 { 6 } 7 8 public function calculate(Product $product) 9 { 10 $taxRate = $this->vatProvider->getRate($product->countryCode()); 11 // some business logic to calculate price 12 } 13 } 14
9. <?php interface VatProvider { public function getRate(string $countryCode): float; } 1 2 3 4 5 6 Extract Interface
10. <?php class CalculatePrice { public function __construct(private VatProvider $vatProvider) { } public function calculate(Product $product) { $taxRate = $this->vatProvider->getRate($product->countryCode()); // some business logic to calculate price } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 public function __construct(private VatProvider $vatProvider) <?php 1 2 class CalculatePrice 3 { 4 5 { 6 } 7 8 public function calculate(Product $product) 9 { 10 $taxRate = $this->vatProvider->getRate($product->countryCode()); 11 // some business logic to calculate price 12 } 13 } 14
11. <?php class TestProvider implements VatProvider { public function __construct(private float $rate) { } public function getRate(string $countryCode) { return $this->rate; } } 1 2 3 4 5 6 7 8 9 10 11 12 13 class TestProvider implements VatProvider <?php 1 2 3 { 4 public function __construct(private float $rate) 5 { 6 } 7 8 public function getRate(string $countryCode) 9 { 10 return $this->rate; 11 } 12 } 13 public function __construct(private float $rate) <?php 1 2 class TestProvider implements VatProvider 3 { 4 5 { 6 } 7 8 public function getRate(string $countryCode) 9 { 10 return $this->rate; 11 } 12 } 13 return $this->rate; <?php 1 2 class TestProvider implements VatProvider 3 { 4 public function __construct(private float $rate) 5 { 6 } 7 8 public function getRate(string $countryCode) 9 { 10 11 } 12 } 13
12. <?php public function itAppliesTheTaxRate() { $calculateTax = new CalculatePrice( new TestProvider(0.25) ); // ... Assert price what expected (with 0.25 tax rate) } 1 2 3 4 5 6 7 8 9 10 $calculateTax = new CalculatePrice( <?php 1 2 public function itAppliesTheTaxRate() 3 { 4 5 new TestProvider(0.25) 6 ); 7 8 // ... Assert price what expected (with 0.25 tax rate) 9 } 10 new TestProvider(0.25) <?php 1 2 public function itAppliesTheTaxRate() 3 { 4 $calculateTax = new CalculatePrice( 5 6 ); 7 8 // ... Assert price what expected (with 0.25 tax rate) 9 } 10
13. THE CASE HIDDEN DEPENDENCY
14. <?php class ProcessPayment { public function __construct() { // ... } public function process(Payment $payment) { // ... } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 public function __construct() <?php 1 2 class ProcessPayment 3 { 4 5 { 6 // ... 7 } 8 9 public function process(Payment $payment) 10 { 11 // ... 12 } 13 } 14
15. <?php public function itRecordsThePayment() { $payment = new Payment(340, 'EUR', 12); $processPayment = new ProcessPayment(); $processpayments->process($payment); // ... Assert stuff } 1 2 3 4 5 6 7 8 9 10 11
16. <?php class ProcessPayment { public function __construct() { // some code $this->mailer = new Mailer('api-key', 'secret'); // some code } public function process(Payment $payment) { // ... $this->mailer->send( $payment->receiver(), new PaymentNotificationMessage($payment) ); } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 $this->mailer = new Mailer('api-key', 'secret'); <?php 1 2 class ProcessPayment 3 { 4 public function __construct() 5 { 6 // some code 7 8 // some code 9 } 10 11 public function process(Payment $payment) 12 { 13 // ... 14 15 $this->mailer->send( 16 $payment->receiver(), 17 new PaymentNotificationMessage($payment) 18 ); 19 20 } 21 } 22 $this->mailer->send( $payment->receiver(), new PaymentNotificationMessage($payment) ); } } <?php 1 2 class ProcessPayment 3 { 4 public function __construct() 5 { 6 // some code 7 $this->mailer = new Mailer('api-key', 'secret'); 8 // some code 9 } 10 11 public function process(Payment $payment) 12 { 13 // ... 14 15 16 17 18 19 20 21 22
17. <?php class ProcessPayment { public function __construct() { $this->mailer = new Mailer('api-key', 'secret'); } public function process(Payment $payment) { // ... } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14
18. <?php class ProcessPayment { public function __construct(Mailer $mailer) { $this->mailer = $mailer; } public function process(Payment $payment) { // ... } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Parameterize Constructor (Extract Interface)
19. DESIGN?
20. dependency injection principle strategy design pattern depend on abstract not a concrete
21. MORE ADVICE?
22. THANK YOU @konrad_126