Unit tests for cache module

tests/test_cache.py

+#!/usr/bin/env python
+#
+# test_cache.py -
+#
+# Author: Paul McCarthy <pauldmccarthy@gmail.com>
+#
+
+import time
+import pytest
+
+import fsl.utils.cache as cache
+
+
+def test_dropOldest():
+    sz = 10
+    c  = cache.Cache(maxsize=sz)
+
+    # Fill the cache
+    for i in range(sz):
+        c.put(i, str(i))
+
+        assert len(c) == i + 1
+
+    # Add an item for an existing key -
+    # no items should be dropped
+    c.put(0, 'New value!')
+    assert c.get(0) == 'New value!'
+    for i in range(1, sz):
+        assert c.get(i) == str(i)
+
+    # Add some more items - the first
+    # items should be dropped
+    for i in range(sz, sz + 5):
+        c.put(i, str(i))
+
+        assert len(c) == sz
+
+    # Check that they've been dropped
+    for i in range(5):
+        with pytest.raises(KeyError):
+            c.get(i)
+
+    # Check that the new items are there
+    for i in range(5, sz + 5):
+        assert c.get(i) == str(i)
+
+
+def test_clear():
+    sz = 10
+    c  = cache.Cache(maxsize=sz)
+
+    # Put some items in
+    for i in range(sz):
+        c.put(i, str(i))
+
+    # Make sure they're there
+    for i in range(sz):
+        assert c.get(i) == str(i)
+
+    # Drop them all
+    c.clear()
+
+    # Make sure they've been dropped
+    assert len(c) == 0
+
+    for i in range(sz):
+        with pytest.raises(KeyError):
+            c.get(i)
+    
+
+def test_getdefault():
+    c = cache.Cache()
+
+    assert c.get('non_existent',         'default') == 'default'
+    assert c.get('non_existent', default='default') == 'default'
+
+    with pytest.raises(KeyError):
+        c.get('non_existent')
+
+    with pytest.raises(ValueError):
+        c.get('non_existent', 'default',        'badarg')
+        c.get('non_existent', 'default', badarg='badarg')
+        c.get('non_existent', 'badarg', default='default')
+        c.get('non_existent', default='default', badarg='badarg') 
+
+
+def test_expiry():
+    c = cache.Cache()
+
+    # Put some items in, with short expiry times
+    c.put(0, '0', expiry=1)
+    c.put(1, '1', expiry=1)
+
+    # Make sure we can get them
+    assert c.get(0) == '0'
+    assert c.get(1) == '1'
+
+    # Wait until they should have expired
+    time.sleep(1.1)
+
+    # Check that the cache has expired
+    with pytest.raises(cache.Expired):
+        c.get(0)
+
+    assert c.get(1, default='default') == 'default'
+
+    # And that the cache is empty
+    assert len(c) == 0