diff --git a/src/Guzzle/Plugin/Mock/MockPlugin.php b/src/Guzzle/Plugin/Mock/MockPlugin.php
index ab7833ce..2440578c 100644
--- a/src/Guzzle/Plugin/Mock/MockPlugin.php
+++ b/src/Guzzle/Plugin/Mock/MockPlugin.php
@@ -226,17 +226,20 @@ class MockPlugin extends AbstractHasDispatcher implements EventSubscriberInterfa
      * Called when a request is about to be sent
      *
      * @param Event $event
+     * @throws \OutOfBoundsException When queue is empty
      */
     public function onRequestBeforeSend(Event $event)
     {
-        if ($this->queue) {
-            $request = $event['request'];
-            $this->received[] = $request;
-            // Detach the filter from the client so it's a one-time use
-            if ($this->temporary && count($this->queue) == 1 && $request->getClient()) {
-                $request->getClient()->getEventDispatcher()->removeSubscriber($this);
-            }
-            $this->dequeue($request);
+        if (!$this->queue) {
+            throw new \OutOfBoundsException('Mock queue is empty');
         }
+
+        $request = $event['request'];
+        $this->received[] = $request;
+        // Detach the filter from the client so it's a one-time use
+        if ($this->temporary && count($this->queue) == 1 && $request->getClient()) {
+            $request->getClient()->getEventDispatcher()->removeSubscriber($this);
+        }
+        $this->dequeue($request);
     }
 }
diff --git a/tests/Guzzle/Tests/Http/Message/RequestFactoryTest.php b/tests/Guzzle/Tests/Http/Message/RequestFactoryTest.php
index d43e0899..f91bc84a 100644
--- a/tests/Guzzle/Tests/Http/Message/RequestFactoryTest.php
+++ b/tests/Guzzle/Tests/Http/Message/RequestFactoryTest.php
@@ -421,7 +421,10 @@ class HttpRequestFactoryTest extends \Guzzle\Tests\GuzzleTestCase
 
     public function testCanAddPlugins()
     {
-        $mock = new MockPlugin(array(new Response(200)));
+        $mock = new MockPlugin(array(
+            new Response(200),
+            new Response(200)
+        ));
         $client = new Client();
         $client->addSubscriber($mock);
         $request = $client->get('/', array(), array(
diff --git a/tests/Guzzle/Tests/Plugin/Cache/DefaultRevalidationTest.php b/tests/Guzzle/Tests/Plugin/Cache/DefaultRevalidationTest.php
index 19bcecac..0699cb26 100644
--- a/tests/Guzzle/Tests/Plugin/Cache/DefaultRevalidationTest.php
+++ b/tests/Guzzle/Tests/Plugin/Cache/DefaultRevalidationTest.php
@@ -176,6 +176,7 @@ class DefaultRevalidationTest extends \Guzzle\Tests\GuzzleTestCase
                 'Last-Modified'  => $lm,
                 'Content-Length' => 2
             ), 'hi'),
+            new CurlException('Bleh'),
             new CurlException('Bleh')
         ));
         $client->addSubscriber(new CachePlugin());
@@ -184,7 +185,7 @@ class DefaultRevalidationTest extends \Guzzle\Tests\GuzzleTestCase
         $response = $client->get()->send();
         $this->assertEquals(200, $response->getStatusCode());
         $this->assertEquals('hi', $response->getBody(true));
-        $this->assertEquals(2, count($mock->getReceivedRequests()));
+        $this->assertEquals(3, count($mock->getReceivedRequests()));
         $this->assertEquals(0, count($mock->getQueue()));
     }
 
@@ -198,6 +199,7 @@ class DefaultRevalidationTest extends \Guzzle\Tests\GuzzleTestCase
                 'Last-Modified' => $lm,
                 'Content-Length' => 2
             ), 'hi'),
+            new CurlException('Oh no!'),
             new CurlException('Oh no!')
         ));
         $cache = new CachePlugin();
diff --git a/tests/Guzzle/Tests/Plugin/Mock/MockPluginTest.php b/tests/Guzzle/Tests/Plugin/Mock/MockPluginTest.php
index 52be8060..3760abdb 100644
--- a/tests/Guzzle/Tests/Plugin/Mock/MockPluginTest.php
+++ b/tests/Guzzle/Tests/Plugin/Mock/MockPluginTest.php
@@ -119,8 +119,9 @@ class MockPluginTest extends \Guzzle\Tests\GuzzleTestCase
 
     /**
      * @depends testAddsResponseFilesToQueue
+     * @expectedException \OutOfBoundsException
      */
-    public function testUpdateIgnoresWhenEmpty()
+    public function testUpdateThrowsExceptionWhenEmpty()
     {
         $p = new MockPlugin();
         $p->onRequestBeforeSend(new Event());