lab/tests/test_library.py

python

import pytest

from library import Book, BookNotAvailableError, Library, Member

from library.storage import load, save

@pytest.fixture

def lib() -> Library:

    lib = Library()

    lib.add_book(Book("1", "Wings of Fire", "A.P.J. Abdul Kalam"))

    lib.add_book(Book("2", "The White Tiger", "Aravind Adiga"))

    lib.add_book(Book("3", "Godan", "Munshi Premchand"))

    lib.add_book(Book("4", "Train to Pakistan", "Khushwant Singh"))

    lib.add_member(Member("M1", "Asha"))

    lib.add_member(Member("M2", "Vikram"))

    return lib

def test_issue_marks_book_unavailable(lib):

    lib.issue_book("1", "M1")

    assert not lib.books["1"].available

    assert lib.members["M1"].borrowed == ["1"]

def test_issue_twice_raises(lib):

    lib.issue_book("1", "M1")

    with pytest.raises(BookNotAvailableError):

        lib.issue_book("1", "M2")

def test_return_makes_available(lib):

    lib.issue_book("1", "M1")

    lib.return_book("1")

    assert lib.books["1"].available

    assert lib.members["M1"].borrowed == []

def test_return_unissued_raises(lib):

    with pytest.raises(ValueError):

        lib.return_book("2")

def test_member_limit(lib):

    for isbn in ["1", "2", "3"]:

        lib.issue_book(isbn, "M1")

    with pytest.raises(ValueError):

        lib.issue_book("4", "M1")

def test_duplicate_isbn_rejected(lib):

    with pytest.raises(ValueError):

        lib.add_book(Book("1", "Copy", "Someone"))

@pytest.mark.parametrize("query, expected", [("wings", 1), ("PREMCHAND", 1), ("tiger", 1), ("zzz", 0)])

def test_search(lib, query, expected):

    assert len(lib.search(query)) == expected

def test_save_and_load_roundtrip(lib, tmp_path):

    lib.issue_book("2", "M2")

    path = tmp_path / "library.json"

    save(lib, path)

    restored = load(path)

    assert restored.books["2"].issued_to == "M2"

    assert restored.members["M2"].borrowed == ["2"]