FEATURE: Book Creation

Purpose

Allow a reader to submit a non-empty title and author and have the book stored in the reading list.

Trigger

The reader submits the book form with POST /books.

Workflow

1. Read the title and author form fields.
2. Pass the submitted values to the book-store boundary.
3. Redirect to / after persistence succeeds.
4. The subsequent list read displays the newly stored book.

Validation of empty fields is owned by FEATURE-Incomplete-Submission.md.

Operational Behavior

• Successful creation uses a redirect response to return the reader to the list.
• The submitted title and author are preserved.
• Existing books retain their relative order.
• Persistence is performed only through BookStore.add.

Programmatic Acceptance

=== AC book-creation-route ===
Intent: The book-creation route accepts a submitted title and author and returns a redirect response.

from app import create_app

title = "Middlemarch" author = "George Eliot" application = create_app({"TESTING": True, "DATABASE": ":memory:"}) response = application.test_client().post( "/books", data={"title": title, "author": author}, )

assert response.status_code in (302, 303) === END AC book-creation-route ===

=== AC book-creation-readback ===
Intent: A successfully submitted book is visible when the list is read again.

from app import create_app

title = "Kindred" author = "Octavia Butler" application = create_app({"TESTING": True, "DATABASE": ":memory:"}) client = application.test_client()

created = client.post("/books", data={"title": title, "author": author}) assert created.status_code in (302, 303) response = client.get("/") body = response.get_data(as_text=True)

assert response.status_code == 200 assert title in body assert author in body === END AC book-creation-readback ===

=== AC book-creation-preserves-existing-order ===
Intent: Adding a new book preserves the relative order of books already present.

from app import create_app

first_title = "First" first_author = "Author One" second_title = "Second" second_author = "Author Two" application = create_app({"TESTING": True, "DATABASE": ":memory:"}) client = application.test_client()

assert client.post("/books", data={"title": first_title, "author": first_author}).status_code in (302, 303) assert client.post("/books", data={"title": second_title, "author": second_author}).status_code in (302, 303) body = client.get("/").get_data(as_text=True)

assert body.index(first_title) < body.index(second_title) === END AC book-creation-preserves-existing-order ===

User Acceptance

• None.

Guardrails

• A book is stored only when both title and author are non-empty.
• Successful submission must make the book visible on the next list read.
• Existing books must not be reordered.