How to Mock Cache Tag Invalidation in Python

import unittest
from unittest.mock import patch

def get_cached_data(cache, key):
    """Return data from cache if present and valid, else None."""
    if cache.get(key, {}).get("valid", False):
        return cache[key]["data"]
    return None

def invalidate_tag_mock(cache, tag):
    """Invalidate all cache entries with the given tag."""
    keys_to_invalidate = [k for k, v in cache.items() if tag in v.get("tags", [])]
    for key in keys_to_invalidate:
        cache[key]["valid"] = False

class TestCacheInvalidation(unittest.TestCase):
    def test_invalidates_tagged_entries(self):
        cache = {
            "user:1": {"data": "alice", "tags": ["user"], "valid": True},
            "user:2": {"data": "bob", "tags": ["user", "admin"], "valid": True},
            "post:1": {"data": "hello", "tags": ["post"], "valid": True},
        }
        
        with patch("__main__.get_cached_data", wraps=get_cached_data) as mock_get:
            invalidate_tag_mock(cache, "user")
            self.assertIsNone(mock_get(cache, "user:1"))
            self.assertIsNone(mock_get(cache, "user:2"))
            self.assertEqual(mock_get(cache, "post:1"), "hello")
            mock_get.assert_called_with(cache, "post:1")

if __name__ == "__main__":
    unittest.main(verbosity=2)