'Returns the serialized course_key for the test'

@property
def course_id(self):

    default_store = os.environ.get('DEFAULT_STORE', 'draft')
    course_key = CourseLocator(self.course_info['org'], self.course_info['number'], self.course_info['run'], deprecated=(default_store == 'draft'))
    return unicode(course_key)
