Add sticky channel option

With this option, all message will be sent to the default channel only.

This is useful for dev environment when you want to concentrate all test message to a specific test channel.

src/Client.php

@@ -21,6 +21,16 @@ class Client
      */
     protected $channel;
 
+    /**
+     * If set to true, all messages will be sent to the default channel,
+     * even if you specify another one during the runtime.
+     *
+     * This is useful for dev environment.
+     *
+     * @var bool
+     */
+    protected $sticky_channel = false;
+
     /**
      * The default username to send messages as.
      *
@@ -95,6 +105,10 @@ public function __construct($endpoint, array $attributes = [], Guzzle $guzzle =
             $this->setDefaultChannel($attributes['channel']);
         }
 
+        if (isset($attributes['sticky_channel'])) {
+            $this->setStickyChannel($attributes['sticky_channel']);
+        }
+
         if (isset($attributes['username'])) {
             $this->setDefaultUsername($attributes['username']);
         }
@@ -181,6 +195,22 @@ public function setDefaultChannel($channel)
         $this->channel = $channel;
     }
 
+    /**
+     * @return bool
+     */
+    public function isStickyChannel()
+    {
+        return $this->sticky_channel;
+    }
+
+    /**
+     * @param bool $sticky_channel
+     */
+    public function setStickyChannel($sticky_channel)
+    {
+        $this->sticky_channel = $sticky_channel;
+    }
+
     /**
      * Get the default username messages will be created for.
      *
@@ -385,7 +415,7 @@ public function preparePayload(Message $message)
     {
         $payload = [
             'text' => $message->getText(),
-            'channel' => $message->getChannel(),
+            'channel' => $this->isStickyChannel() ? $this->channel : $message->getChannel(),
             'username' => $message->getUsername(),
             'link_names' => $this->getLinkNames() ? 1 : 0,
             'unfurl_links' => $this->getUnfurlLinks(),

tests/ClientFunctionalTest.php

@@ -317,6 +317,31 @@ public function testMessageWithAttachmentsAndActions()
         $this->assertEquals($expectedHttpData, $payload);
     }
 
+    public function testMessageWithStickyChannel()
+    {
+        $expectedHttpData = [
+            'username' => 'Archer',
+            'channel' => 'test',
+            'text' => 'Message',
+            'link_names' => 0,
+            'unfurl_links' => false,
+            'unfurl_media' => true,
+            'mrkdwn' => true,
+            'attachments' => [],
+        ];
+
+        $client = new Client('http://fake.endpoint', [
+            'channel' => 'test',
+            'sticky_channel' => true,
+        ]);
+
+        $message = $client->to('@regan')->from('Archer')->setText('Message');
+
+        $payload = $client->preparePayload($message);
+
+        $this->assertEquals($expectedHttpData, $payload);
+    }
+
     public function testBadEncodingThrowsException()
     {
         $client = $this->getNetworkStubbedClient();