Be able to throw exceptions

Add responseReceived event which is triggered directly after the
performed call.

Add ThrowExceptionOnFailurePlugin which listens to the responseReceived
event and throws an exception on failures.

README.md

@@ -40,3 +40,15 @@ $mailer->send($message);
 
 ?>
 ```
+
+##### 3. Throw exceptions on Postmark api errors
+
+```php
+$transport = new \Postmark\Transport('<SERVER_TOKEN>');
+$transport->registerPlugin(new \Postmark\ThrowExceptionOnFailurePlugin());
+
+$message = new Swift_Message('Hello from Postmark!');
+$mailer->send($message); // Exception is throw when response !== 200
+
+?>
+```

src/Postmark/ThrowExceptionOnFailurePlugin.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Postmark;
+
+class ThrowExceptionOnFailurePlugin implements \Swift_Events_ResponseListener
+{
+    public function responseReceived(\Swift_Events_ResponseEvent $event)
+    {
+        if (!$event->isValid()) {
+            throw new \Swift_TransportException($event->getResponse());
+        }
+    }
+}

src/Postmark/Transport.php

@@ -74,9 +74,9 @@ public function ping() {
 	public function send(Swift_Mime_SimpleMessage $message, &$failedRecipients = null) {
 		$client = $this->getHttpClient();
 
-		if ($evt = $this->_eventDispatcher->createSendEvent($this, $message)) {
-			$this->_eventDispatcher->dispatchEvent($evt, 'beforeSendPerformed');
-			if ($evt->bubbleCancelled()) {
+		if ($sendEvent = $this->_eventDispatcher->createSendEvent($this, $message)) {
+			$this->_eventDispatcher->dispatchEvent($sendEvent, 'beforeSendPerformed');
+			if ($sendEvent->bubbleCancelled()) {
 				return 0;
 			}
 		}
@@ -94,14 +94,18 @@ public function send(Swift_Mime_SimpleMessage $message, &$failedRecipients = nul
 			'http_errors' => false,
 		]);
 
-		$sendSuccessful = $response->getStatusCode() == 200;
+		$success = $response->getStatusCode() === 200;
 
-		if ($evt && $sendSuccessful) {
-			$evt->setResult(\Swift_Events_SendEvent::RESULT_SUCCESS);
-			$this->_eventDispatcher->dispatchEvent($evt, 'sendPerformed');
+		if ($responseEvent = $this->_eventDispatcher->createResponseEvent($this, $response->getBody()->getContents(), $success)) {
+			$this->_eventDispatcher->dispatchEvent($responseEvent, 'responseReceived');
+		}
+
+		if ($sendEvent) {
+			$sendEvent->setResult($success ? \Swift_Events_SendEvent::RESULT_SUCCESS : \Swift_Events_SendEvent::RESULT_FAILED);
+			$this->_eventDispatcher->dispatchEvent($sendEvent, 'sendPerformed');
 		}
 
-		return $sendSuccessful
+		return $success
 			? $this->getRecipientCount($message)
 			: 0;
 	}

tests/ThrowExceptionOnFailurePluginTest.php

@@ -0,0 +1,34 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use Postmark\ThrowExceptionOnFailurePlugin;
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+class ThrowExceptionOnFailurePluginTest extends TestCase {
+
+    /**
+     * @doesNotPerformAssertions
+     */
+    public function testValidResponseThrowsNoException()
+    {
+        $valid = true;
+        $event = new \Swift_Events_ResponseEvent(new \Postmark\Transport('SERVER_TOKEN'), 'success', $valid);
+
+        $plugin = new ThrowExceptionOnFailurePlugin();
+        $plugin->responseReceived($event); // no exception
+    }
+
+    public function testInvalidResponseThrowsException()
+    {
+        $valid = false;
+        $event = new \Swift_Events_ResponseEvent(new \Postmark\Transport('SERVER_TOKEN'), 'invalid response', $valid);
+
+        $plugin = new ThrowExceptionOnFailurePlugin();
+
+        $this->expectException(\Swift_TransportException::class);
+        $this->expectExceptionMessage('invalid response');
+
+        $plugin->responseReceived($event);
+    }
+}

tests/TransportTest.php

@@ -146,9 +146,20 @@ public function testToAndCcCanBeNullableEvents()
 
     public function testServerTokenReturnedFromPublicMethod()
     {
-        $transport = new PostmarkTransportStub([new Response(200)]);
+        $transport = new PostmarkTransportStub();
         $this->assertEquals($transport->getServerToken(), 'TESTING_SERVER');
     }
+
+    public function testFailedResponse()
+    {
+        $message = new Swift_Message();
+
+        $transport = new PostmarkTransportStub([new Response(401)]);
+        $transport->registerPlugin(new \Postmark\ThrowExceptionOnFailurePlugin());
+
+        $this->expectException(\Swift_TransportException::class);
+        $transport->send($message);
+    }
 }