diff --git a/lib/Cake/tests/Case/View/MediaViewTest.php b/lib/Cake/tests/Case/View/MediaViewTest.php
index 47f6b9b9b39..d0f4be9607f 100644
--- a/lib/Cake/tests/Case/View/MediaViewTest.php
+++ b/lib/Cake/tests/Case/View/MediaViewTest.php
@@ -117,7 +117,7 @@ function testRender() {
  * @return void
  */
 	function testRenderWithUnknownFileTypeGeneric() {
-		$currentUserAgent = $_SERVER['HTTP_USER_AGENT'];
+		$currentUserAgent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null;
 		$_SERVER['HTTP_USER_AGENT'] = 'Some generic browser';
 		$this->MediaView->viewVars = array(
 			'path' =>  LIBS . 'tests' . DS . 'test_app' . DS . 'config' . DS,
@@ -165,7 +165,9 @@ function testRenderWithUnknownFileTypeGeneric() {
 		$output = ob_get_clean();
 		$this->assertEqual("some_key = some_value\nbool_key = 1\n", $output);
 		$this->assertTrue($result !== false);
-		$_SERVER['HTTP_USER_AGENT'] = $currentUserAgent;
+		if ($currentUserAgent !== null) {
+			$_SERVER['HTTP_USER_AGENT'] = $currentUserAgent;
+		}
 	}
 
 /**
@@ -175,7 +177,7 @@ function testRenderWithUnknownFileTypeGeneric() {
  * @return void
  */
 	function testRenderWithUnknownFileTypeOpera() {
-		$currentUserAgent = $_SERVER['HTTP_USER_AGENT'];
+		$currentUserAgent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null;
 		$_SERVER['HTTP_USER_AGENT'] = 'Opera/9.80 (Windows NT 6.0; U; en) Presto/2.8.99 Version/11.10';
 		$this->MediaView->viewVars = array(
 			'path' =>  LIBS . 'tests' . DS . 'test_app' . DS . 'config' . DS,
@@ -228,7 +230,9 @@ function testRenderWithUnknownFileTypeOpera() {
 		$output = ob_get_clean();
 		$this->assertEqual("some_key = some_value\nbool_key = 1\n", $output);
 		$this->assertTrue($result !== false);
-		$_SERVER['HTTP_USER_AGENT'] = $currentUserAgent;
+		if ($currentUserAgent !== null) {
+			$_SERVER['HTTP_USER_AGENT'] = $currentUserAgent;
+		}
 	}
 
 /**
@@ -238,7 +242,7 @@ function testRenderWithUnknownFileTypeOpera() {
  * @return void
  */
 	function testRenderWithUnknownFileTypeIE() {
-		$currentUserAgent = $_SERVER['HTTP_USER_AGENT'];
+		$currentUserAgent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null;
 		$_SERVER['HTTP_USER_AGENT'] = 'Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; Media Center PC 4.0; SLCC1; .NET CLR 3.0.04320)';
 		$this->MediaView->viewVars = array(
 			'path' =>  LIBS . 'tests' . DS . 'test_app' . DS . 'config' . DS,
@@ -291,7 +295,9 @@ function testRenderWithUnknownFileTypeIE() {
 		$output = ob_get_clean();
 		$this->assertEqual("some_key = some_value\nbool_key = 1\n", $output);
 		$this->assertTrue($result !== false);
-		$_SERVER['HTTP_USER_AGENT'] = $currentUserAgent;
+		if ($currentUserAgent !== null) {
+			$_SERVER['HTTP_USER_AGENT'] = $currentUserAgent;
+		}
 	}
 
 /**