'Checks that bad filter directive raise.'

def testBadFilterRaises(self):

    conf = config_lib.GrrConfigManager()
    conf.DEFINE_string('Section1.foo6', '%(somefile@somepackage|resource)', 'test')
    conf.DEFINE_string('Section1.foo1', '%(Section1.foo6)/bar', 'test')
    conf.Initialize(data='')
    with self.assertRaises(config_lib.InterpolationError) as context:
        _ = conf['Section1.foo1']
    self.assertTrue(('%(Section1.foo6)/bar' in str(context.exception)))
