public function testForceCookieExpiry()
 {
     Injector::inst()->registerService(new CookieJar(['testCookie' => 'not so yum']), 'Cookie_Backend');
     $this->assertEquals('not so yum', Cookie::get('testCookie'));
     Utilities::force_cookie_expiry('testCookie');
     $this->assertEmpty(Cookie::get('testCookie'));
 }