Fixed #20: I can parse simple concepts

tests/caching/test_FastCache.py

@@ -51,6 +51,15 @@ def test_not_found_is_returned_when_not_found():
     assert cache.get("foo") is NotFound
 
 
+def test_i_can_remove_an_item():
+    cache = FastCache()
+    cache.put("key1", "value1")
+    cache.put("to_keep1", "to_keep_value1")
+
+    cache.remove("key1")
+    assert cache.cache == {"to_keep1": "to_keep_value1"}
+
+
 def test_i_can_evict_by_key():
     cache = FastCache()
     cache.put("key1", "value1")
@@ -109,3 +118,33 @@ def test_i_can_copy():
     cache.put("key3", "value3")
 
     assert cache.copy() == {"key1": "value1", "key2": "value2", "key3": "value3"}
+
+
+def test_i_can_take_snapshots_and_revert():
+    # Test that I can create restoration points
+    # and come back later to them
+    cache = FastCache()
+    cache.put("key1", "value1")
+    cache.snapshot()
+    cache.put("key2", "value2")
+    cache.put("key3", "value3")
+    cache.snapshot()
+    cache.put("key4", "value4")
+    cache.put("key5", "value5")
+
+    assert cache.cache == {"key1": "value1",
+                           "key2": "value2",
+                           "key3": "value3",
+                           "key4": "value4",
+                           "key5": "value5"}
+
+    cache.revert_snapshot()
+    assert cache.cache == {"key1": "value1",
+                           "key2": "value2",
+                           "key3": "value3"}
+
+    cache.revert_snapshot()
+    assert cache.cache == {"key1": "value1"}
+
+    cache.revert_snapshot()  # no effect if nothing to revert
+    assert cache.cache == {"key1": "value1"}