72 - Extracting a Finder Method

app/Http/Controllers/OrdersController.php

@@ -9,7 +9,7 @@ class OrdersController extends Controller
 {
     public function show($confirmationNumber)
     {
-        $order = Order::where('confirmation_number', $confirmationNumber)->first();
+        $order = Order::findByConfirmationNumber($confirmationNumber);
         return view('orders.show', ['order' => $order]);
     }
 }

app/Order.php

@@ -22,6 +22,11 @@ class Order extends Model
         return $order;
     }
 
+    public static function findByConfirmationNumber($confirmationNumber)
+    {
+        return self::where('confirmation_number', $confirmationNumber)->firstOrFail();
+    }
+
     public function concert()
     {
         return $this->belongsTo(Concert::class);

tests/unit/OrderTest.php

@@ -7,6 +7,7 @@ use App\Reservation;
 use Illuminate\Foundation\Testing\WithoutMiddleware;
 use Illuminate\Foundation\Testing\DatabaseMigrations;
 use Illuminate\Foundation\Testing\DatabaseTransactions;
+use Illuminate\Database\Eloquent\ModelNotFoundException;
 
 class OrderTest extends TestCase
 {
@@ -26,6 +27,30 @@ class OrderTest extends TestCase
         $this->assertEquals(2, $concert->ticketsRemaining());
     }
 
+    /** @test */
+    function retrieving_an_order_by_confirmation_number()
+    {
+        $order = factory(Order::class)->create([
+            'confirmation_number' => 'ORDERCONFIRMATION1234',
+        ]);
+
+        $foundOrder = Order::findByConfirmationNumber('ORDERCONFIRMATION1234');
+
+        $this->assertEquals($order->id, $foundOrder->id);
+    }
+
+    /** @test */
+    function retrieving_a_nonexistent_order_by_confirmation_number_throws_an_exception()
+    {
+        try {
+            Order::findByConfirmationNumber('NONEXISTENTCONFIRMATIONNUMBER');
+        } catch (ModelNotFoundException $e) {
+            return;
+        }
+
+        $this->fail('No matching order was found for the specified confirmation number, but an exception was not thrown.');
+    }
+
     /** @test */
     function converting_to_an_array()
     {