import unittest
import functools

class LRUCacheTest(unittest.TestCase):

    def test_as_wrapper(self):

        @functools.lru_cache()
        def factorial(n):
            if n == 0:
                return 1
            else:
                return n * factorial(n-1)
        
        factorial(20)
        self.assertEqual(21, factorial.cache_info().misses)

    def test_as_function_with_rename(self):
                
        def factorial(n):
            if n == 0:
                return 1
            else:
                return n * factorial(n-1)

        f = functools.lru_cache()(factorial)
        f(20)
        self.assertEqual(21, f.cache_info().misses)

    def test_as_function(self):
                
        def factorial(n):
            if n == 0:
                return 1
            else:
                return n * factorial(n-1)

        factorial = functools.lru_cache()(factorial)
        factorial(20)
        self.assertEqual(21, factorial.cache_info().misses)

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