6.5 - Hooking into Charges

app/Billing/FakePaymentGateway.php

@@ -5,6 +5,7 @@ namespace App\Billing;
 class FakePaymentGateway implements PaymentGateway
 {
     private $charges;
+    private $beforeFirstChargeCallback;
 
     public function __construct()
     {
@@ -18,6 +19,10 @@ class FakePaymentGateway implements PaymentGateway
 
     public function charge($amount, $token)
     {
+        if ($this->beforeFirstChargeCallback !== null) {
+            $this->beforeFirstChargeCallback->__invoke($this);
+        }
+
         if ($token !== $this->getValidTestToken()) {
             throw new PaymentFailedException;
         }
@@ -28,4 +33,9 @@ class FakePaymentGateway implements PaymentGateway
     {
         return $this->charges->sum();
     }
+
+    public function beforeFirstCharge($callback)
+    {
+        $this->beforeFirstChargeCallback = $callback;
+    }
 }

tests/unit/Billing/FakePaymentGatewayTest.php

@@ -30,4 +30,20 @@ class FakePaymentGatewayTest extends TestCase
 
         $this->fail();
     }
+
+    /** @test */
+    function running_a_hook_before_the_first_charge()
+    {
+        $paymentGateway = new FakePaymentGateway;
+        $callbackRan = false;
+
+        $paymentGateway->beforeFirstCharge(function ($paymentGateway) use (&$callbackRan) {
+            $callbackRan = true;
+            $this->assertEquals(0, $paymentGateway->totalCharges());
+        });
+
+        $paymentGateway->charge(2500, $paymentGateway->getValidTestToken());
+        $this->assertTrue($callbackRan);
+        $this->assertEquals(2500, $paymentGateway->totalCharges());
+    }
 }