diff --git a/composer.json b/composer.json
index 5df9a5355b..339211f6f0 100644
--- a/composer.json
+++ b/composer.json
@@ -76,7 +76,8 @@
 		"phpdocumentor/reflection-docblock": "^3.0.2",
 		"phpunit/php-token-stream": "^1.4.2",
 		"mikey179/vfsStream": "^1.6",
-		"mockery/mockery": "^1.2"
+		"mockery/mockery": "^1.2",
+		"johnkary/phpunit-speedtrap": "1.1"
 	},
 	"scripts": {
 		"test": "phpunit"
diff --git a/composer.lock b/composer.lock
index 9230bb4db9..16b9e50b52 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "9f0dbeccbae197460a0ce74a940177cd",
+    "content-hash": "ee7a6d8a1a9df21b46478dd91c1b73b7",
     "packages": [
         {
             "name": "asika/simple-console",
@@ -2059,6 +2059,54 @@
             ],
             "time": "2016-01-20T08:20:44+00:00"
         },
+        {
+            "name": "johnkary/phpunit-speedtrap",
+            "version": "v1.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/johnkary/phpunit-speedtrap.git",
+                "reference": "f7cfe17c5a7076ed0ccca5450fe3bb981ec56361"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/johnkary/phpunit-speedtrap/zipball/f7cfe17c5a7076ed0ccca5450fe3bb981ec56361",
+                "reference": "f7cfe17c5a7076ed0ccca5450fe3bb981ec56361",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6",
+                "phpunit/phpunit": ">=4.7,<6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.1-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "JohnKary": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "John Kary",
+                    "email": "john@johnkary.net"
+                }
+            ],
+            "description": "Find slow tests in your PHPUnit test suite",
+            "homepage": "https://github.com/johnkary/phpunit-speedtrap",
+            "keywords": [
+                "phpunit",
+                "profile",
+                "slow"
+            ],
+            "time": "2017-03-25T17:14:26+00:00"
+        },
         {
             "name": "mikey179/vfsStream",
             "version": "v1.6.5",
diff --git a/phpunit.xml b/phpunit.xml
index 9ed293b631..0209ce6aa2 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -26,4 +26,7 @@
 	<logging>
 		<log type="coverage-clover" target="clover.xml" />
 	</logging>
+	<listeners>
+		<listener class="JohnKary\PHPUnit\Listener\SpeedTrapListener" />
+	</listeners>
 </phpunit>
diff --git a/tests/src/Core/Cache/CacheTest.php b/tests/src/Core/Cache/CacheTest.php
index 86bf5e7f01..e51ce745f0 100644
--- a/tests/src/Core/Cache/CacheTest.php
+++ b/tests/src/Core/Cache/CacheTest.php
@@ -123,6 +123,8 @@ abstract class CacheTest extends DatabaseTest
 	 * @medium
 	 */
 	function testTTL() {
+		$this->markTestSkipped('taking too much time without mocking');
+
 		$this->assertNull($this->instance->get('value1'));
 
 		$value = 'foobar';
diff --git a/tests/src/Core/Lock/LockTest.php b/tests/src/Core/Lock/LockTest.php
index a7bbea265f..78f2271e54 100644
--- a/tests/src/Core/Lock/LockTest.php
+++ b/tests/src/Core/Lock/LockTest.php
@@ -116,6 +116,8 @@ abstract class LockTest extends DatabaseTest
 	 * @medium
 	 */
 	function testLockTTL() {
+		$this->markTestSkipped('taking too much time without mocking');
+
 		$this->assertFalse($this->instance->isLocked('foo'));
 		$this->assertFalse($this->instance->isLocked('bar'));