fastmcp/tests/utilities/test_cache.py
2025-05-09 18:06:51 -04:00

233 lines
7.9 KiB
Python

"""Tests for the cache.py module."""
import datetime
import time
from unittest.mock import patch
from fastmcp.utilities.cache import TimedCache
class TestTimedCache:
"""Tests for the TimedCache class."""
def test_init(self):
"""Test that a TimedCache can be initialized with an expiration."""
expiration = datetime.timedelta(seconds=10)
cache = TimedCache(expiration)
assert cache.expiration == expiration
assert isinstance(cache.cache, dict)
assert len(cache.cache) == 0
def test_set(self):
"""Test that values can be set in the cache."""
cache = TimedCache(datetime.timedelta(seconds=10))
key, value = "test_key", "test_value"
with patch("datetime.datetime") as mock_datetime:
now = datetime.datetime(2023, 1, 1, tzinfo=datetime.timezone.utc)
mock_datetime.now.return_value = now
cache.set(key, value)
# Check that the value is stored with the correct expiration
assert key in cache.cache
stored_value, expiration = cache.cache[key]
assert stored_value == value
assert expiration == now + datetime.timedelta(seconds=10)
def test_get_found(self):
"""Test retrieving a value that exists and has not expired."""
cache = TimedCache(datetime.timedelta(seconds=10))
key, value = "test_key", "test_value"
# Set a future expiration time
future = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
seconds=30
)
cache.cache[key] = (value, future)
# The value should be returned
assert cache.get(key) == value
def test_get_expired(self):
"""Test retrieving a value that exists but has expired."""
cache = TimedCache(datetime.timedelta(seconds=10))
key, value = "test_key", "test_value"
# Set a past expiration time
past = datetime.datetime.now(datetime.timezone.utc) - datetime.timedelta(
seconds=1
)
cache.cache[key] = (value, past)
# Should return NOT_FOUND
assert cache.get(key) is TimedCache.NOT_FOUND
def test_get_not_found(self):
"""Test retrieving a value that doesn't exist in the cache."""
cache = TimedCache(datetime.timedelta(seconds=10))
# Key doesn't exist
assert cache.get("nonexistent_key") is TimedCache.NOT_FOUND
def test_clear(self):
"""Test that the cache can be cleared."""
cache = TimedCache(datetime.timedelta(seconds=10))
# Add some items
cache.set("key1", "value1")
cache.set("key2", "value2")
assert len(cache.cache) == 2
# Clear the cache
cache.clear()
assert len(cache.cache) == 0
def test_real_expiration(self):
"""Test that values actually expire after the specified time."""
# Use a very short expiration for the test
cache = TimedCache(datetime.timedelta(milliseconds=50))
key, value = "test_key", "test_value"
cache.set(key, value)
# Value should be available immediately
assert cache.get(key) == value
# Wait for expiration
time.sleep(0.06) # 60 milliseconds, slightly longer than expiration
# Value should now be expired
assert cache.get(key) is TimedCache.NOT_FOUND
def test_overwrite_value(self):
"""Test that setting a key that already exists overwrites the old value."""
cache = TimedCache(datetime.timedelta(seconds=10))
key = "test_key"
# Set initial value
cache.set(key, "initial_value")
assert cache.get(key) == "initial_value"
# Overwrite with new value
cache.set(key, "new_value")
assert cache.get(key) == "new_value"
def test_extends_expiration_on_overwrite(self):
"""Test that overwriting a key extends its expiration time."""
cache = TimedCache(datetime.timedelta(seconds=10))
key = "test_key"
with patch("datetime.datetime") as mock_datetime:
# Set initial value at t=0
initial_time = datetime.datetime(2023, 1, 1, tzinfo=datetime.timezone.utc)
mock_datetime.now.return_value = initial_time
cache.set(key, "initial_value")
initial_expiration = cache.cache[key][1]
assert initial_expiration == initial_time + datetime.timedelta(seconds=10)
# Overwrite at t=5
later_time = initial_time + datetime.timedelta(seconds=5)
mock_datetime.now.return_value = later_time
cache.set(key, "new_value")
# Expiration should be extended
new_expiration = cache.cache[key][1]
assert new_expiration == later_time + datetime.timedelta(seconds=10)
def test_different_key_types(self):
"""Test that different types of keys can be used."""
cache = TimedCache(datetime.timedelta(seconds=10))
# Test various key types
keys_and_values = [
(42, "int_value"),
(3.14, "float_value"),
((1, 2), "tuple_value"),
(frozenset({1, 2, 3}), "frozenset_value"),
]
for key, value in keys_and_values:
cache.set(key, value)
assert cache.get(key) == value
def test_none_value(self):
"""Test that None can be stored as a value."""
cache = TimedCache(datetime.timedelta(seconds=10))
key = "none_key"
cache.set(key, None)
# The stored value is None, but get() should return None, not NOT_FOUND
assert cache.get(key) is None
def test_edge_case_zero_expiration(self):
"""Test with a zero expiration time."""
cache = TimedCache(datetime.timedelta(seconds=0))
key, value = "test_key", "test_value"
cache.set(key, value)
# The value might already be expired by the time we call get()
# We can't make strong assertions here due to timing variability
retrieved = cache.get(key)
assert retrieved in (value, TimedCache.NOT_FOUND)
def test_negative_expiration(self):
"""Test with a negative expiration time."""
cache = TimedCache(datetime.timedelta(seconds=-1))
key, value = "test_key", "test_value"
cache.set(key, value)
# Value should be immediately expired
assert cache.get(key) is TimedCache.NOT_FOUND
def test_cache_consistency(self):
"""Test cache consistency with multiple operations."""
cache = TimedCache(datetime.timedelta(seconds=10))
# Add multiple items
cache.set("key1", "value1")
cache.set("key2", "value2")
cache.set("key3", "value3")
# Check all items
assert cache.get("key1") == "value1"
assert cache.get("key2") == "value2"
assert cache.get("key3") == "value3"
# Overwrite one item
cache.set("key2", "updated_value")
# Check again
assert cache.get("key1") == "value1"
assert cache.get("key2") == "updated_value"
assert cache.get("key3") == "value3"
# Clear and verify all items are gone
cache.clear()
assert cache.get("key1") is TimedCache.NOT_FOUND
assert cache.get("key2") is TimedCache.NOT_FOUND
assert cache.get("key3") is TimedCache.NOT_FOUND
def test_large_expiration(self):
"""Test with a very large expiration time."""
# One year expiration
cache = TimedCache(datetime.timedelta(days=365))
key, value = "test_key", "test_value"
cache.set(key, value)
assert cache.get(key) == value
def test_many_items(self):
"""Test cache with many items."""
cache = TimedCache(datetime.timedelta(seconds=10))
# Add 1000 items
for i in range(1000):
cache.set(f"key{i}", f"value{i}")
# Check size
assert len(cache.cache) == 1000
# Check some random items
for i in [0, 123, 456, 789, 999]:
assert cache.get(f"key{i}") == f"value{i}"