diff --git a/tests/lib/memcache/castrait.php b/tests/lib/memcache/castrait.php
new file mode 100644
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+++ b/tests/lib/memcache/castrait.php
@@ -0,0 +1,73 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace Test\Memcache;
+
+use Test\TestCase;
+
+class CasTrait extends TestCase {
+	/**
+	 * @return \OC\Memcache\CasTrait
+	 */
+	private function getCache() {
+		$sourceCache = new \OC\Memcache\ArrayCache();
+		$mock = $this->getMockForTrait('\OC\Memcache\CasTrait');
+
+		$mock->expects($this->any())
+			->method('set')
+			->will($this->returnCallback(function ($key, $value, $ttl) use ($sourceCache) {
+				return $sourceCache->set($key, $value, $ttl);
+			}));
+
+		$mock->expects($this->any())
+			->method('get')
+			->will($this->returnCallback(function ($key) use ($sourceCache) {
+				return $sourceCache->get($key);
+			}));
+
+		$mock->expects($this->any())
+			->method('add')
+			->will($this->returnCallback(function ($key, $value, $ttl) use ($sourceCache) {
+				return $sourceCache->add($key, $value, $ttl);
+			}));
+
+		$mock->expects($this->any())
+			->method('remove')
+			->will($this->returnCallback(function ($key) use ($sourceCache) {
+				return $sourceCache->remove($key);
+			}));
+		return $mock;
+	}
+
+	public function testCasNotChanged() {
+		$cache = $this->getCache();
+		$cache->set('foo', 'bar');
+		$this->assertTrue($cache->cas('foo', 'bar', 'asd'));
+		$this->assertEquals('asd', $cache->get('foo'));
+	}
+
+	public function testCasChanged() {
+		$cache = $this->getCache();
+		$cache->set('foo', 'bar1');
+		$this->assertFalse($cache->cas('foo', 'bar', 'asd'));
+		$this->assertEquals('bar1', $cache->get('foo'));
+	}
+}