def test_cache_lookup(self):
cache = LRUCache(4)
for x in ['a', 'b', 'c', 'd']:
cache[x] = x
for x in ['a', 'b', 'c', 'd']:
self.assertEqual(x, cache[x])
def test_cache_overflow(self):
cache = LRUCache(3)
for x in ['a', 'b', 'c', 'd']:
cache[x] = x
for x in ['b', 'c', 'd']:
self.assertEqual(x, cache[x])
with self.assertRaises(KeyError):
_ = cache['a']
_ = cache['b']
_ = cache['d']
# 'c' should be LRU now
cache['e'] = 'e'
with self.assertRaises(KeyError):
_ = cache['c']
for x in ['b', 'd', 'e']:
self.assertEqual(x, cache[x])
def test_cache_no_entry(self):
cache = LRUCache(3)
with self.assertRaises(KeyError):
_ = cache['a']