def test_validation(self):
cache_name = self.check_cache_gone('validation')
cache = PersistentCache(cache_name, cache_manager=self.manager, contents={ 'foo': 'bar' },
validator=lambda *args: False, builder=lambda *args: ['built'])
cache.save()
cache.load_or_build() # Invalid load, force rebuild
self.assert_contents_equal(cache, ['built'])
cache[0] = 'changed'
cache.save()
cache.validator = lambda *args: True
cache.load()
self.assert_contents_equal(cache, ['changed'])
# Raising an exception in validator should invalidate the cache
cache.validator = lambda *args: args['not legal']
cache.load()
self.assert_contents_equal(cache, None)
