Accept optional rejection reason for ConnectionManagerReject

Author: clue

README.md

@@ -96,10 +96,21 @@ $delayed = new ConnectionManagerDelayed($connector, 0.5, $loop);
 
 ### Reject
 
-The `ConnectionManagerReject()` simply rejects every single connection attempt.
+The `ConnectionManagerReject(?string $reason)` simply rejects every single connection attempt.
 This is particularly useful for the below [`ConnectionManagerSelective`](#selective) to reject connection attempts
 to only certain destinations (for example blocking advertisements or harmful sites).
 
+The constructor accepts an optional rejection reason which will be used for the
+`Exception` instance that is used to reject the resulting promise.
+
+```php
+$connector = new ConnectionManagerReject('Blocked');
+$connector->connect('www.google.com:80')->then(null, function ($e) {
+    assert($e instanceof \Exception);
+    assert($e->getMessage() === 'Blocked');
+});
+```
+
 ### Swappable
 
 The `ConnectionManagerSwappable($connector)` is a simple decorator for other `ConnectionManager`s to

src/ConnectionManagerReject.php

@@ -9,8 +9,21 @@
 // a simple connection manager that rejects every single connection attempt
 class ConnectionManagerReject implements ConnectorInterface
 {
+    private $reason = 'Connection rejected';
+
+    /**
+     *
+     * @param ?string $reason
+     */
+    public function __construct($reason = null)
+    {
+        if ($reason !== null) {
+            $this->reason = $reason;
+        }
+    }
+
     public function connect($_)
     {
-        return Promise\reject(new Exception('Connection rejected'));
+        return Promise\reject(new Exception($this->reason));
     }
 }

tests/ConnectionManagerRejectTest.php

@@ -13,4 +13,17 @@ public function testReject()
 
         $promise->then($this->expectCallableNever(), $this->expectCallableOnce());
     }
+
+    public function testRejectWithCustomMessage()
+    {
+        $cm = new ConnectionManagerReject('Blocked');
+        $promise = $cm->connect('www.google.com:80');
+
+        $text = null;
+        $promise->then($this->expectCallableNever(), function (Exception $e) use (&$text) {
+            $text = $e->getMessage();
+        });
+
+        $this->assertEquals('Blocked', $text);
+    }
 }