create testcase, use stub and mock

app/Interfaces/INotify.php

@@ -0,0 +1,10 @@
+<?php
+
+
+namespace App\Interfaces;
+
+
+interface INotify
+{
+    public function notify(\Exception $exception): string;
+}

app/Listeners/WriteSumToLog.php

@@ -4,21 +4,28 @@
 
 use App\Events\StringWasAdded;
 use App\Interfaces\ILoggerService;
+use App\Interfaces\INotify;
 
 class WriteSumToLog
 {
     /**
      * @var ILoggerService
      */
     private $loggerService;
+    /**
+     * @var INotify
+     */
+    private $notifyService;
 
     /**
      * WriteSumToLog constructor.
      * @param ILoggerService $loggerService
+     * @param INotify $notifyService
      */
-    public function __construct(ILoggerService $loggerService)
+    public function __construct(ILoggerService $loggerService, INotify $notifyService)
     {
         $this->loggerService = $loggerService;
+        $this->notifyService = $notifyService;
     }
 
     /**
@@ -29,6 +36,10 @@ public function __construct(ILoggerService $loggerService)
      */
     public function handle(StringWasAdded $event)
     {
-        $this->loggerService->write($event->sum);
+        try {
+            $this->loggerService->write($event->sum);
+        } catch (\Exception $exception) {
+            $this->notifyService->notify($exception);
+        }
     }
 }

app/Providers/AppServiceProvider.php

@@ -3,7 +3,9 @@
 namespace App\Providers;
 
 use App\Interfaces\ILoggerService;
+use App\Interfaces\INotify;
 use App\Services\LaravelLoggerService;
+use App\Services\LoggerNotifyService;
 use Illuminate\Support\ServiceProvider;
 
 class AppServiceProvider extends ServiceProvider
@@ -16,6 +18,7 @@ class AppServiceProvider extends ServiceProvider
     public function register()
     {
         $this->app->singleton(ILoggerService::class, LaravelLoggerService::class);
+        $this->app->singleton(INotify::class, LoggerNotifyService::class);
     }
 
     /**

app/Services/LoggerNotifyService.php

@@ -0,0 +1,15 @@
+<?php
+
+
+namespace App\Services;
+
+
+use App\Interfaces\INotify;
+
+class LoggerNotifyService implements INotify
+{
+    public function notify(\Exception $exception): string
+    {
+        return $exception->getMessage();
+    }
+}

app/Services/StringCalculatorService.php

@@ -2,7 +2,6 @@
 
 namespace App\Services;
 
-use App\Events\StringCalculatorAdded;
 use App\Events\StringWasAdded;
 use App\Exceptions\StringCalculatorServiceException;
 

tests/Services/StringCalculatorServiceTest.php

@@ -5,9 +5,12 @@
 use App\Events\StringWasAdded;
 use App\Exceptions\StringCalculatorServiceException;
 use App\Interfaces\ILoggerService;
+use App\Interfaces\INotify;
 use App\Services\StringCalculatorService;
+use Exception;
 use Illuminate\Support\Facades\Event;
 use Mockery;
+use Mockery\MockInterface;
 use Tests\TestCase;
 
 /**
@@ -198,6 +201,25 @@ public function longerMultipleDelimitersProvider()
         ];
     }
 
+    /**
+     * @test
+     * 嘗試不同的測試案例命名方式
+     */
+    public function CallAdd_LogFailAndThrowException_GetExceptionMessageLogFail()
+    {
+        // stub: When calling Add() and the logger throws an exception
+        $this->instance(ILoggerService::class, new StubLoggerService());
+        $stubLoggerService = $this->app->make(ILoggerService::class);
+        $stubLoggerService->toThrow = true;
+
+        // mock: call notify() when writing log fail.
+        $this->mock(INotify::class)
+            ->shouldReceive('notify')
+            ->once();
+
+        $this->stringCalculatorService->add('');
+    }
+
     /**
      * @test
      */
@@ -251,10 +273,24 @@ protected function tearDown(): void
     }
 
     /**
-     * @return Mockery\MockInterface
+     * @return MockInterface
      */
-    private function mockLoggerInterface(): Mockery\MockInterface
+    private function mockLoggerInterface(): MockInterface
     {
         return $this->mock(ILoggerService::class);
     }
 }
+
+class StubLoggerService implements ILoggerService
+{
+    public $toThrow = false;
+
+    /**
+     * @param string $log
+     * @param string $level
+     */
+    public function write(string $log, string $level = 'info'): void
+    {
+        throw_if($this->toThrow, Exception::class);
+    }
+}