commit 52ee1d7a8bdc36dacf555cf46c1fa3cfc163480d
Author: cutsweettea <swagastan@proton.me>
Date:   Tue Sep 30 15:25:40 2025 -0400

    yessir

diff --git a/book_stuff/book.py b/book_stuff/book.py
new file mode 100644
index 0000000..0c546bd
--- /dev/null
+++ b/book_stuff/book.py
@@ -0,0 +1,107 @@
+"""
+This file is the beginnings of a Book class.  However, it isn't very well-coded.
+We want to harden it.  We want to enforce the following rules:
+
+- Title must not be blank, and cannot be longer than 255 characters.
+- Authors is a list of names.  None of the names should be blank or over 255 characters.
+  Names should not have any characters except for alphabetical ones.
+- ISBN is a string, but it can only contain numbers and there must be 13 of them.
+- Cost cannot be negative.
+
+We are going to practice "test-driven development".  This means we will write
+the test cases for our code before we write our code.  Enough of the code is
+already given to you to show you how to use it.  Don't update the code until
+you have written tests to check for all of the above criteria.  When your code passes
+your tests, have your neighbor email you their tests and see if theirs passes as well.
+If not, modify your code accordingly.
+"""
+class Book:
+    def __init__(self, title: str, authors: list[str], isbn: str, cost: float):
+        self.set_title(title)
+        self.set_authors(authors)
+        self.set_isbn(isbn)
+        self.set_cost(cost)
+
+    # --- Title ---
+    def get_title(self) -> str:
+        return self._title
+
+    def set_title(self, title: str) -> None:
+        # check if title is string
+        if not isinstance(title, str):
+            raise TypeError(f'title must be of type str, not {type(title).__name__}')
+        
+        # check if title is blank or if the title length is greater than 255 characters
+        title_len = len(title)
+        if title_len < 1 or title_len > 255:
+            raise TypeError(f'title\'s length must be between 1 and 255, not {title_len}')
+        
+        self._title = title
+
+    # --- Authors ---
+    def get_authors(self) -> list[str]:
+        return self._authors
+
+    def set_authors(self, authors: list[str]) -> None:
+        # check if authors is a list
+        if not isinstance(authors, list):
+            raise TypeError(f'authors must be of type list, not {type(authors).__name__}')
+        
+        # check if authors is empty
+        authors_len = len(authors)
+        if authors_len == 0:
+            raise ValueError('authors list must not be empty')
+        
+        for author in authors:
+            # check if each author is a string
+            if not isinstance(author, str):
+                raise TypeError(f'each author within authors must be of type str, not {type(author).__name__}')
+            
+            # check if each author is alphanumeric
+            for author_name_part in author.split():
+                # splitting by space to check each part of the author's name, spaces aren't alpha so no author.isalpha()
+                if not author_name_part.isalpha():
+                    raise ValueError(f'each part of the author\'s name within authors must be alphanumeric')
+            
+            # check if each author's length is greater than 255
+            author_len = len(author)
+            if author_len > 255:
+                raise ValueError(f'each author\'s length within authors must be less than 256 characters')
+            
+        self._authors = authors
+
+    # --- ISBN ---
+    def get_isbn(self) -> str:
+        return self._isbn
+
+    def set_isbn(self, isbn: str) -> None:
+        # check is isbn is 13 characters
+        isbn_len = len(isbn)
+        if isbn_len != 13:
+            raise ValueError(f'isbn\'s length must be 13 digits, not {isbn_len}')
+        
+        # check if each character is a number
+        if not isbn.isdigit():
+            raise ValueError('each character in isbn must be a digit')
+        
+        self._isbn = isbn
+
+    # --- Cost ---
+    def get_cost(self) -> float:
+        return self._cost
+
+    def set_cost(self, cost: float) -> None:
+        # check if cost is float
+        if not isinstance(cost, float):
+            raise ValueError(f'cost must be of type float, not {type(cost).__name__}')
+
+        # check if cost is negative
+        if cost < 0:
+            raise ValueError("cost cannot be negative")
+        
+        self._cost = cost
+
+    # --- String representation ---
+    def __str__(self) -> str:
+        authors = ", ".join(self._authors)
+        return f"'{self._title}' by {authors} (ISBN: {self._isbn}, Cost: ${self._cost:.2f})"
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diff --git a/book_stuff/test_book.py b/book_stuff/test_book.py
new file mode 100644
index 0000000..0b4325f
--- /dev/null
+++ b/book_stuff/test_book.py
@@ -0,0 +1,96 @@
+import pytest
+
+from book import Book
+
+_default_title = 'My Boke'
+_default_authors = ['Eliott Wootton', 'John Smith']
+_default_isbn = '1234567890123'
+_default_cost = 14.99
+
+@pytest.fixture
+def valid_book():
+    return Book(_default_title, _default_authors, _default_isbn, _default_cost)
+
+# test if book setter works
+def test_create_valid_book(valid_book: Book):
+    assert valid_book.get_title() == _default_title
+    assert valid_book.get_authors() == _default_authors
+    assert valid_book.get_isbn() == _default_isbn
+    assert valid_book.get_cost() == _default_cost
+
+# test if title setter works
+def test_update_title(valid_book: Book):
+    valid_book.set_title('My Book')
+    assert valid_book.get_title() == 'My Book'
+
+# test if authors setter works
+def test_update_authors(valid_book: Book):
+    valid_book.set_authors(['John Smith', 'Jane Smith'])
+    assert valid_book.get_authors() == ['John Smith', 'Jane Smith']
+
+# test if isbn setter works
+def test_update_isbn(valid_book: Book):
+    valid_book.set_isbn('3210987654321')
+    assert valid_book.get_isbn() == '3210987654321'
+
+# test is cost setter works
+def test_update_cost(valid_book: Book):
+    valid_book.set_cost(9.99)
+    assert valid_book.get_cost() == 9.99
+
+# test if repr works
+def test_repr_str(valid_book):
+    rep = str(valid_book)
+    assert _default_title in rep
+    assert ', '.join(_default_authors) in rep
+    assert _default_isbn in rep
+    assert str(_default_cost) in rep
+
+"""
+- Title must not be blank, and cannot be longer than 255 characters.
+- Authors is a list of names.  None of the names should be blank or over 255 characters.
+  Names should not have any characters except for alphabetical ones.
+- ISBN is a string, but it can only contain numbers and there must be 13 of them.
+- Cost cannot be negative.
+"""
+
+# test if empty, length > 255, and if string
+@pytest.mark.parametrize("invalid_title", [
+    "",
+    "A" * 256,
+    6.7
+])
+def test_invalid_title_raises(invalid_title: str):
+    with pytest.raises((ValueError, TypeError)):
+        Book(invalid_title, _default_authors, _default_isbn, _default_cost)
+
+# test if empty, is array, each author's name is str, each author's name > 255 and each author's name alpha
+@pytest.mark.parametrize("invalid_authors", [
+    [],
+    'Eliott Wootton',
+    [41, 'Charleston White'],
+    ['LeBron James', 'A'*256],
+    ['3liott W00tt0n', 'hello world']
+])
+def test_invalid_authors_raised(invalid_authors: str):
+    with pytest.raises((ValueError, TypeError)):
+        Book(_default_title, invalid_authors, _default_isbn, _default_cost)
+
+# test if string, only contains numbers and length is 13
+@pytest.mark.parametrize("invalid_isbn", [
+    127,
+    '123456789o123',
+    '12345678901234'
+])
+def test_invalid_isbn_raises(invalid_isbn: str):
+    with pytest.raises((ValueError, TypeError)):
+        Book(_default_title, _default_authors, invalid_isbn, _default_cost)
+
+# test if float and not negative
+@pytest.mark.parametrize("invalid_cost", [
+    '14.99',
+    -14.99
+])
+def test_invalid_cost_raises(invalid_cost: str):
+    with pytest.raises((ValueError, TypeError)):
+        Book(_default_title, _default_authors, _default_isbn, invalid_cost)
\ No newline at end of file