Why are no tests shown on testing overview? I want to run DrupalWebTestCases on my custom Drupal 7 module.

Following the Tutorial at https://drupal.org/simpletest-tutorial-drupal7 i'm stuck at running the tests:
also after cache deletion no other Tests than for SimpleTest are found on the /admin/config/development/testing-page.

I'm using the contributed SimpleTest module, added the testing_api = 2.x setting to my modules .info.

mymodule/mymodule.info:

name = Mymodule Reports
core = 7.x
php = 5.3
files[] = tests/*.test
testing_api = 2.x


mymodule/tests/mymodule.test:
    

/**
 * @file
 * Mymodule reports module tests.
 */

class MymoduleReportsTestCase extends DrupalWebTestCase {

  public static function getInfo() {
    return array(
      'name' =&gt; 'MymoduleReports',
      'description' =&gt; 'Ensure that the locking of nodes functions properly.',
      'group' =&gt; 'Mymodule',
    );
  }

}


What i'm doing wrong?
Instead of using 

files[] = tests/*.test


in mymodule/mymodule.info
it should be

files[] = tests/mymodule.test