Add MongoDB-backed NotesTool with CRUD actions and unit tests (#1982)

* Add MongoDB-backed NotesTool with CRUD actions and unit tests

* NotesTool: enforce single note per user, require decoded_token['sub'] user_id, fix tests

* chore: remove accidentally committed results.txt and ignore it

* fix: remove results.txt, enforce single note per user, add tests

* refactor: update NotesTool actions and tests for clarity and consistency

* refactor: update NotesTool docstring for clarity

* refactor: simplify MCPTool docstring and remove redundant import in test_notes_tool

* lint: fix test

* refactor: remove unused import from test_notes_tool.py

---------

Co-authored-by: Alex <a@tushynski.me>

tests/test_notes_tool.py

@@ -0,0 +1,133 @@
+import pytest
+from application.agents.tools.notes import NotesTool
+from application.core.settings import settings
+
+
+
+@pytest.fixture
+def notes_tool(monkeypatch) -> NotesTool:
+    """Provide a NotesTool with a fake Mongo collection and fixed user_id."""
+    class FakeCollection:
+        def __init__(self) -> None:
+            self.doc = None  # single note per user
+
+        def update_one(self, q, u, upsert=False):
+            # emulate single-note storage with optional upsert
+            if self.doc is None and not upsert:
+                return type("res", (), {"modified_count": 0})
+            if self.doc is None and upsert:
+                self.doc = {"user_id": q["user_id"], "note": ""}
+            if "$set" in u and "note" in u["$set"]:
+                self.doc["note"] = u["$set"]["note"]
+            return type("res", (), {"modified_count": 1})
+
+        def find_one(self, q):
+            if self.doc and self.doc.get("user_id") == q.get("user_id"):
+                return self.doc
+            return None
+
+        def delete_one(self, q):
+            if self.doc and self.doc.get("user_id") == q.get("user_id"):
+                self.doc = None
+                return type("res", (), {"deleted_count": 1})
+            return type("res", (), {"deleted_count": 0})
+
+    fake_collection = FakeCollection()
+    fake_db = {"notes": fake_collection}
+    fake_client = {settings.MONGO_DB_NAME: fake_db}
+
+    # Patch MongoDB client globally for the tool
+    monkeypatch.setattr("application.core.mongo_db.MongoDB.get_client", lambda: fake_client)
+
+    # ToolManager will pass user_id in production; in tests we pass it directly
+    return NotesTool({}, user_id="test_user")
+
+
+def test_view(notes_tool: NotesTool) -> None:
+    # Manually insert a note to test retrieval
+    notes_tool.collection.update_one(
+        {"user_id": "test_user"},
+        {"$set": {"note": "hello"}},
+        upsert=True
+    )
+    assert "hello" in notes_tool.execute_action("view")
+
+
+def test_overwrite_and_delete(notes_tool: NotesTool) -> None:
+    # Overwrite creates a new note
+    assert "saved" in notes_tool.execute_action("overwrite", text="first").lower()
+    assert "first" in notes_tool.execute_action("view")
+
+    # Overwrite replaces existing note
+    assert "saved" in notes_tool.execute_action("overwrite", text="second").lower()
+    assert "second" in notes_tool.execute_action("view")
+
+    assert "deleted" in notes_tool.execute_action("delete").lower()
+    assert "no note" in notes_tool.execute_action("view").lower()
+
+def test_init_without_user_id(monkeypatch):
+    """Should fail gracefully if no user_id is provided."""
+    notes_tool = NotesTool(tool_config={})
+    result = notes_tool.execute_action("view")
+    assert "user_id" in str(result).lower()
+
+
+def test_view_not_found(notes_tool: NotesTool) -> None:
+    """Should return 'No note found.' when no note exists"""
+    result = notes_tool.execute_action("view")
+    assert "no note found" in result.lower()
+
+
+def test_str_replace(notes_tool: NotesTool) -> None:
+    """Test string replacement in note"""
+    # Create a note
+    notes_tool.execute_action("overwrite", text="Hello world, hello universe")
+
+    # Replace text
+    result = notes_tool.execute_action("str_replace", old_str="hello", new_str="hi")
+    assert "updated" in result.lower()
+
+    # Verify replacement
+    note = notes_tool.execute_action("view")
+    assert "hi world, hi universe" in note.lower()
+
+
+def test_str_replace_not_found(notes_tool: NotesTool) -> None:
+    """Test string replacement when string not found"""
+    notes_tool.execute_action("overwrite", text="Hello world")
+    result = notes_tool.execute_action("str_replace", old_str="goodbye", new_str="hi")
+    assert "not found" in result.lower()
+
+
+def test_insert_line(notes_tool: NotesTool) -> None:
+    """Test inserting text at a line number"""
+    # Create a multiline note
+    notes_tool.execute_action("overwrite", text="Line 1\nLine 2\nLine 3")
+
+    # Insert at line 2
+    result = notes_tool.execute_action("insert", line_number=2, text="Inserted line")
+    assert "inserted" in result.lower()
+
+    # Verify insertion
+    note = notes_tool.execute_action("view")
+    lines = note.split("\n")
+    assert lines[1] == "Inserted line"
+    assert lines[2] == "Line 2"
+
+
+def test_delete_nonexistent_note(monkeypatch):
+    class FakeResult:
+        deleted_count = 0
+
+    class FakeCollection:
+        def delete_one(self, *args, **kwargs):
+            return FakeResult()
+
+    monkeypatch.setattr(
+        "application.core.mongo_db.MongoDB.get_client",
+        lambda: {"docsgpt": {"notes": FakeCollection()}}
+    )
+
+    notes_tool = NotesTool(tool_config={}, user_id="user123")
+    result = notes_tool.execute_action("delete")
+    assert "no note found" in result.lower()