diff --git a/tests/ConnectionTest.php b/tests/ConnectionTest.php
index 2325e80..7246b85 100644
--- a/tests/ConnectionTest.php
+++ b/tests/ConnectionTest.php
@@ -67,4 +67,28 @@ class ConnectionTest extends TestCase
 
         $connection->assertSentEvent('pusher:pong');
     }
+
+    /** @test */
+    public function clients_can_subscribe_to_channels()
+    {
+        /** @var PusherServer $server */
+        $server = app(PusherServer::class);
+
+        $connection = $this->getWebSocketConnection();
+
+        $message = new Message(json_encode([
+            'event' => 'pusher:subscribe',
+            'data' => [
+                'channel' => 'basic-channel'
+            ],
+        ]));
+
+        $server->onOpen($connection);
+
+        $server->onMessage($connection, $message);
+
+        $connection->assertSentEvent('pusher_internal:subscription_succeeded', [
+            'channel' => 'basic-channel'
+        ]);
+    }
 }
\ No newline at end of file
diff --git a/tests/Mocks/Connection.php b/tests/Mocks/Connection.php
index e1b0f20..e004d9a 100644
--- a/tests/Mocks/Connection.php
+++ b/tests/Mocks/Connection.php
@@ -11,7 +11,7 @@ class Connection implements ConnectionInterface
     /** @var Request */
     public $httpRequest;
 
-    protected $sentData = [];
+    public $sentData = [];
 
     function send($data)
     {
@@ -23,10 +23,16 @@ class Connection implements ConnectionInterface
         // TODO: Implement close() method.
     }
 
-    public function assertSentEvent(string $name)
+    public function assertSentEvent(string $name, array $additionalParameters = [])
     {
+        $event = collect($this->sentData)->firstWhere('event', '=', $name);
+
         PHPUnit::assertTrue(
-            ! is_null(collect($this->sentData)->firstWhere('event', '=', $name))
+            ! is_null($event)
         );
+
+        foreach ($additionalParameters as $parameter => $value) {
+            PHPUnit::assertSame($event[$parameter], $value);
+        }
     }
 }
\ No newline at end of file