Add delete and remove operations for entry management

tests/test_dbengine.py

@@ -1,3 +1,4 @@
+import json
 import os.path
 import shutil
 
@@ -73,6 +74,15 @@ def dummy_obj_with_ref():
   return DummyObjWithRef(1, "a", data)
 
 
+def load_head(engine, tenant_id):
+  head_path = os.path.join(engine._get_user_root(tenant_id), engine.HeadFile)
+  try:
+    with open(head_path, 'r') as file:
+      return json.load(file)
+  except FileNotFoundError:
+    return {}
+
+
 def test_i_can_test_init():
   if os.path.exists(DB_ENGINE_ROOT):
     shutil.rmtree(DB_ENGINE_ROOT)
@@ -271,3 +281,59 @@ def test_i_can_retrieve_history_using_save(engine):
   assert v2["key1"] == DummyObj(1, "a", False)
   
   assert v2[TAG_PARENT] == [None]
+
+
+def test_i_can_delete_entries(engine):
+  digest1 = engine.save(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry", {"key1": DummyObj(1, "a", False)})
+  digest2 = engine.save(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry2", {"key1": DummyObj(2, "b", True)})
+  res = engine.delete(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry")
+  
+  assert res is True
+  
+  # entry is no longer in the head
+  head = load_head(engine, FAKE_TENANT_ID)
+  assert "MyEntry" not in head
+  assert "MyEntry2" in head
+  
+  # digests are not removed from the db
+  assert engine.load(FAKE_TENANT_ID, "MyEntry2", digest1) is not None
+  assert engine.load(FAKE_TENANT_ID, "MyEntry2", digest2) is not None
+
+
+def test_i_can_delete_an_entry_that_does_not_exist(engine):
+  # no exception should be raised
+  res = engine.delete(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry")
+  assert res is False
+
+
+def test_i_can_remove_an_key_from_an_entry(engine):
+  engine.save(FAKE_TENANT_ID,
+              FAKE_USER_EMAIL,
+              "MyEntry",
+              {
+                  "key1": DummyObj(1, "a", False),
+                  "key2": DummyObj(2, "b", True)
+              })
+  
+  res = engine.remove(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry", "key1")
+  assert res is True
+  
+  snapshot = engine.load(FAKE_TENANT_ID, "MyEntry")
+  assert "key1" not in snapshot
+  assert "key2" in snapshot
+
+
+def test_i_can_remove_a_key_that_does_not_exist(engine):
+  # no exception should be raised
+  res = engine.remove(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry", "key1")
+  assert res is False
+
+
+def test_removing_the_last_key_from_an_entry_not_not_delete_the_entry(engine):
+  engine.save(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry", {"key1": DummyObj(1, "a", False)})
+  res = engine.remove(FAKE_TENANT_ID, FAKE_USER_EMAIL, "MyEntry", "key1")
+  assert res is True
+  
+  snapshot = engine.load(FAKE_TENANT_ID, "MyEntry")
+  assert "key1" not in snapshot
+  assert snapshot[TAG_PARENT] is not None