fix: automated fixes for PR #24

.gitignore

@@ -9,3 +9,6 @@
 
 # macOS
 .DS_Store
+
+# Environment / secrets
+.env

Dockerfile

@@ -3,5 +3,7 @@ RUN apt-get update && apt-get install -y libpq-dev
 COPY . /app
 WORKDIR /app
 RUN pip install -r requirements.txt
+RUN adduser --disabled-password --gecos "" appuser
+USER appuser
 EXPOSE 8000
-CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000", "--log-level", "trace"]
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000", "--log-level", "warning"]

conftest.py

@@ -1,11 +1,12 @@
 import pytest
-from sqlalchemy import create_engine, inspect, text
+from sqlalchemy import create_engine, inspect
 from sqlalchemy.orm import sessionmaker
 from fastapi.testclient import TestClient
 from main import create_app
 from dependencies import get_db, database_url
 from models import Base
 
+
 @pytest.fixture(scope="session")
 def test_engine():
     """Create test database engine"""
@@ -32,14 +33,22 @@ def test_db(test_engine):
         connection.close()
 
 
-@pytest.fixture
+@pytest.fixture(scope="function")
 def test_app(test_engine):
-    """Create test FastAPI application with test database"""
+    """Create test FastAPI application with test database.
+
+    Uses a single connection with savepoint-based rollback so that data
+    written during a request is visible within the same test function but
+    is rolled back at the end of the test.
+    """
+    connection = test_engine.connect()
+    transaction = connection.begin()
+    TestingSessionLocal = sessionmaker(
+        autocommit=False, autoflush=False, bind=connection,
+        join_transaction_mode="create_savepoint"
+    )
 
     def override_get_db():
-        TestingSessionLocal = sessionmaker(
-            autocommit=False, autoflush=False, bind=test_engine
-        )
         db = TestingSessionLocal()
         try:
             yield db
@@ -48,10 +57,13 @@ def override_get_db():
 
     app = create_app()
     app.dependency_overrides[get_db] = override_get_db
-    return app
+    yield app
 
+    transaction.rollback()
+    connection.close()
 
-@pytest.fixture
+
+@pytest.fixture(scope="function")
 def client(test_app):
     """Create test client"""
     return TestClient(test_app)

docker-compose.yml

@@ -23,8 +23,6 @@ services:
       POSTGRES_DB: ${POSTGRES_DB}
       POSTGRES_USER: ${POSTGRES_USER}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
-    ports:
-      - "5432:5432"
     volumes:
       - postgres_data:/var/lib/postgresql/data
       - ./db.sql:/docker-entrypoint-initdb.d/db.sql

models.py

@@ -1,6 +1,7 @@
+import re
 from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
 from sqlalchemy import String
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, field_validator
 
 
 # SQLAlchemy models
@@ -18,13 +19,27 @@ class Book(Base):
     id: Mapped[int] = mapped_column(primary_key=True, index=True)
     title: Mapped[str] = mapped_column(String(255), index=True)
     author: Mapped[str] = mapped_column(String(255))
+    isbn: Mapped[str] = mapped_column(String(13))
+
 
 # Pydantic models
 class BookIn(BaseModel):
     """Pydantic model for book input"""
 
     title: str
     author: str
+    isbn: str
+
+    @field_validator("isbn")
+    @classmethod
+    def validate_isbn(cls, v: str) -> str:
+        """Validate ISBN-10 or ISBN-13 format."""
+        if not re.match(r"^(?:\d{9}[\dX]|\d{13})$", v):
+            raise ValueError(
+                "isbn must be a valid ISBN-10 (9 digits + digit or X) "
+                "or ISBN-13 (13 digits)"
+            )
+        return v
 
 
 class BookOut(BaseModel):
@@ -33,5 +48,6 @@ class BookOut(BaseModel):
     id: int
     title: str
     author: str
+    isbn: str
 
     model_config = ConfigDict(from_attributes=True)

repositories.py

@@ -4,7 +4,7 @@
 
 # Create a new book
 def create_book(db: Session, book: models.BookIn):
-    db_book = models.Book(title=book.title, author=book.author)
+    db_book = models.Book(title=book.title, author=book.author, isbn=book.isbn)
     db.add(db_book)
     db.commit()
     db.refresh(db_book)
@@ -27,6 +27,7 @@ def update_book(db: Session, book_id: int, book: models.BookIn):
     if db_book:
         db_book.title = book.title
         db_book.author = book.author
+        db_book.isbn = book.isbn
         db.commit()
         db.refresh(db_book)
         return db_book

routers.py

@@ -1,10 +1,12 @@
-from fastapi import APIRouter, Depends, HTTPException, status
+import logging
+from fastapi import APIRouter, Depends, HTTPException, Query, status
 from sqlalchemy.orm import Session
-from typing import List
 import models
 import repositories
 from dependencies import get_db
 
+logger = logging.getLogger(__name__)
+
 # Create router with prefix
 router = APIRouter()
 
@@ -16,19 +18,29 @@ def create_book(book: models.BookIn, db: Session = Depends(get_db)):
     try:
         return repositories.create_book(db=db, book=book)
     except Exception as e:
-        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(e))
+        logger.error("Error creating book: %s", e)
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="An error occurred processing your request",
+        ) from e
 
 
 @router.get(
-    "/books/", response_model=List[models.BookOut], status_code=status.HTTP_200_OK
+    "/books/", response_model=list[models.BookOut], status_code=status.HTTP_200_OK
 )
-def get_books(skip: int = 0, limit: int = 10, db: Session = Depends(get_db)):
+def get_books(
+    skip: int = Query(default=0, ge=0),
+    limit: int = Query(default=10, ge=1, le=100),
+    db: Session = Depends(get_db),
+):
     try:
         return repositories.get_books(db=db, skip=skip, limit=limit)
     except Exception as e:
+        logger.error("Error retrieving books: %s", e)
         raise HTTPException(
-            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(e)
-        )
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail="An error occurred processing your request",
+        ) from e
 
 
 @router.get(