Feat: add get portfolio adapter

src/adapters/portfolio.py

@@ -3,7 +3,7 @@
 from pymongo import MongoClient
 from pymongo.database import Database
 from .base import AbstractPortfolioRepository
-from domain.portfolio import Portfolio
+from domain.portfolio import Portfolio, Holding
 
 
 class PortfolioRepository(AbstractPortfolioRepository):
@@ -12,6 +12,23 @@ def __init__(self, mongo_client: MongoClient, database_name: str = "stock_db"):
         self.db: Database = self.client[database_name]
         self.collection = self.db["portfolio"]
 
+    def get(self, user_id: int) -> Portfolio:
+        result = self.collection.find_one({"user_id": user_id})
+        if result is None:
+            return None
+
+        return Portfolio(
+            user_id=result["user_id"],
+            cash_balance=result["cash_balance"],
+            total_money_in=result["total_money_in"],
+            holdings=[
+                Holding(symbol=holding["symbol"], shares=holding["shares"], total_cost=holding["total_cost"])
+                for holding in result["holdings"]
+            ],
+            created_at=result["created_at"],
+            updated_at=result["updated_at"],
+        )
+
     def update(self, portfolio: Portfolio) -> None:
         portfolio.updated_at = datetime.now(timezone.utc)
         self.collection.replace_one({"user_id": portfolio.user_id}, asdict(portfolio), upsert=True)

src/tests/test_portfolio_adapters.py

@@ -1,5 +1,6 @@
 import pytest
 from datetime import datetime, timezone
+from unittest.mock import ANY
 from dataclasses import asdict
 from pymongo import MongoClient
 from domain.portfolio import Portfolio, Holding
@@ -60,7 +61,7 @@ def test_update_existing_portfolio(self, portfolio_repository):
             created_at=datetime.now(timezone.utc),
             updated_at=datetime.now(timezone.utc),
         )
-        result = portfolio_repository.collection.insert_one(asdict(initial_portfolio))
+        portfolio_repository.collection.insert_one(asdict(initial_portfolio))
 
         updated_portfolio = Portfolio(
             user_id=1,
@@ -84,3 +85,49 @@ def test_update_existing_portfolio(self, portfolio_repository):
         assert result["holdings"][0]["symbol"] == "AAPL"
         assert result["holdings"][0]["shares"] == 20
         assert result["holdings"][0]["total_cost"] == 3000.0
+
+    def test_get_existing_portfolio(self, portfolio_repository):
+        # Arrange
+        created_at = datetime.now(timezone.utc)
+        portfolio = Portfolio(
+            user_id=1,
+            cash_balance=1000.0,
+            total_money_in=1000.0,
+            holdings=[Holding(symbol="AAPL", shares=10, total_cost=1500.0)],
+            created_at=created_at,
+            updated_at=created_at,
+        )
+        portfolio_repository.collection.insert_one(asdict(portfolio))
+        expected_result = Portfolio(
+            user_id=1,
+            cash_balance=1000.0,
+            total_money_in=1000.0,
+            holdings=[Holding(symbol="AAPL", shares=10, total_cost=1500.0)],
+            created_at=ANY,
+            updated_at=ANY,
+        )
+
+        # Action
+        result = portfolio_repository.get(user_id=1)
+
+        # Assertion
+        assert result == expected_result
+
+    def test_get_non_existent_portfolio(self, portfolio_repository):
+        # Arrange
+        created_at = datetime.now(timezone.utc)
+        portfolio = Portfolio(
+            user_id=1,
+            cash_balance=1000.0,
+            total_money_in=1000.0,
+            holdings=[Holding(symbol="AAPL", shares=10, total_cost=1500.0)],
+            created_at=created_at,
+            updated_at=created_at,
+        )
+        portfolio_repository.collection.insert_one(asdict(portfolio))
+
+        # Action
+        result = portfolio_repository.get(user_id=999)
+
+        # Assertion
+        assert result is None