Fix unit tests

src/Messages/ThreemaAudioMessage.php

@@ -53,7 +53,7 @@ private function calculateDuration(): int
 			$ffmpeg = FFProbe::create();
 			$audio = $ffmpeg->format($this->path);
 
-			return $audio->get('duration');
+			return (int)$audio->get('duration');
 		} catch(Exception $exception) {
 			throw new ThreemaChannelException('The underlying FFMpeg has thrown an exception.', 0, $exception);
 		}

src/Messages/ThreemaVideoMessage.php

@@ -92,7 +92,7 @@ private function calculateDuration(): int
 			$ffmpeg = FFProbe::create();
 			$audio = $ffmpeg->format($this->path);
 
-			return $audio->get('duration');
+			return (int)$audio->get('duration');
 		} catch(Exception $exception) {
 			throw new ThreemaChannelException('The underlying FFMpeg has thrown an exception.', 0, $exception);
 		}

tests/Unit/Channels/ThreemaChannelTest.php

@@ -620,7 +620,7 @@ public function routeNotificationForThreema(mixed $notification): Receiver
 
 class ThreemaChannelTextMessageNotificationTest extends Notification
 {
-	public function toThreema(mixed $notifiable): ThreemaMessage
+	public function toThreema(mixed $notifiable): ThreemaTextMessage
 	{
 		$message = new ThreemaTextMessage('Hello World');
 		$message->setText('Hello World!');
@@ -749,7 +749,7 @@ public function __construct(ThreemaChannel $channel)
 		$this->channel = $channel;
 	}
 
-	public function toThreema(mixed $notifiable): ThreemaMessage
+	public function toThreema(mixed $notifiable): ThreemaTextMessage
 	{
 		$message = new ThreemaTextMessage('Hello World!', null);
 		$message->setChannel($this->channel);