Commandes groupées

Reviewed-on: #8

my-library/src/App.jsx

@@ -10,6 +10,10 @@ import BookDetail from './pages/BookDetail';
 import Customers from './pages/Customers';
 import Login from './pages/Login';
 import Reservations from './pages/Reservations';
+import Returns from './pages/Returns';
+import Subscription from './pages/Subscription';
+import Loans from './pages/Loans';
+import GroupOrders from './pages/GroupOrders';
 import { useAuth } from './context/AuthContext';
 
 function RequireAuth({ children }) {
@@ -37,6 +41,10 @@ export default function App() {
         <Route path="reservations" element={<RequireAuth><Reservations /></RequireAuth>} />
         <Route path="profile" element={<RequireAuth><Profile /></RequireAuth>} />
         <Route path="customers" element={<RequireAdmin><Customers /></RequireAdmin>} />
+        <Route path="returns" element={<RequireAdmin><Returns /></RequireAdmin>} />
+        <Route path="subscription" element={<RequireAuth><Subscription /></RequireAuth>} />
+        <Route path="loans" element={<RequireAuth><Loans /></RequireAuth>} />
+        <Route path="group-orders" element={<RequireAuth><GroupOrders /></RequireAuth>} />
         <Route path="*" element={<NotFound />} />
       </Route>
     </Routes>

my-library/src/api/orders.js

@@ -0,0 +1,5 @@
+import client from './client';
+
+export function createOrder(order) {
+  return client.post('/api/orders', order);
+}

my-library/src/components/Navbar.jsx

@@ -20,8 +20,12 @@ export default function Navbar() {
         <li><Link to="/books">Catalogue</Link></li>
         {user && <li><Link to="/orders">Commandes</Link></li>}
         {user?.role === 'user' && <li><Link to="/reservations">Mes réservations</Link></li>}
+        {user?.role === 'user' && <li><Link to="/subscription">Mon abonnement</Link></li>}
+        {user?.role === 'user' && <li><Link to="/loans">Mes prêts</Link></li>}
+        {user && <li><Link to="/group-orders">Commandes groupées</Link></li>}
         {user && <li><Link to="/profile">Mon compte</Link></li>}
         {user?.role === 'admin' && <li><Link to="/customers">Clients</Link></li>}
+        {user?.role === 'admin' && <li><Link to="/returns">Retours</Link></li>}
       </ul>
 
       <div className="navbar__actions">

my-library/src/context/GroupOrderContext.js

@@ -0,0 +1,59 @@
+import { createContext, useContext, useState } from 'react';
+
+const GroupOrderContext = createContext(null);
+
+export function GroupOrderProvider({ children }) {
+  const [groups, setGroups] = useState(() => {
+    const saved = localStorage.getItem('groupOrders');
+    return saved ? JSON.parse(saved) : [];
+  });
+
+  function createGroup(creatorPhone) {
+    const group = {
+      id: crypto.randomUUID(),
+      creatorPhone,
+      orders: [],
+      status: 'OPEN',
+      createdAt: new Date().toISOString(),
+    };
+    const updated = [...groups, group];
+    setGroups(updated);
+    localStorage.setItem('groupOrders', JSON.stringify(updated));
+    return group;
+  }
+
+  function addOrderToGroup(groupId, phoneNumber, bookId, bookTitle, quantity) {
+    const updated = groups.map(g => {
+      if (g.id !== groupId) return g;
+      const order = {
+        orderId: crypto.randomUUID(),
+        phoneNumber,
+        bookId,
+        bookTitle,
+        quantity: Number(quantity),
+        addedAt: new Date().toISOString(),
+      };
+      return { ...g, orders: [...g.orders, order] };
+    });
+    setGroups(updated);
+    localStorage.setItem('groupOrders', JSON.stringify(updated));
+  }
+
+  function closeGroup(groupId) {
+    const updated = groups.map(g =>
+      g.id === groupId ? { ...g, status: 'CLOSED' } : g
+    );
+    setGroups(updated);
+    localStorage.setItem('groupOrders', JSON.stringify(updated));
+  }
+
+  return (
+    <GroupOrderContext.Provider value={{ groups, createGroup, addOrderToGroup, closeGroup }}>
+      {children}
+    </GroupOrderContext.Provider>
+  );
+}
+
+export function useGroupOrders() {
+  return useContext(GroupOrderContext);
+}

my-library/src/context/LoanContext.js

@@ -0,0 +1,45 @@
+import { createContext, useContext, useState } from 'react';
+
+const LoanContext = createContext(null);
+
+export function LoanProvider({ children }) {
+  const [loans, setLoans] = useState(() => {
+    const saved = localStorage.getItem('loans');
+    return saved ? JSON.parse(saved) : [];
+  });
+
+  function addLoan(book, borrowerPhone, dueDate) {
+    const loan = {
+      loanId: crypto.randomUUID(),
+      bookId: book.isbn,
+      bookTitle: book.title,
+      bookAuthor: book.author,
+      borrowerPhone,
+      dueDate,
+      status: 'ACTIVE',
+      loanedAt: new Date().toISOString(),
+    };
+    const updated = [...loans, loan];
+    setLoans(updated);
+    localStorage.setItem('loans', JSON.stringify(updated));
+    return loan;
+  }
+
+  function returnLoan(loanId) {
+    const updated = loans.map(l =>
+      l.loanId === loanId ? { ...l, status: 'RETURNED' } : l
+    );
+    setLoans(updated);
+    localStorage.setItem('loans', JSON.stringify(updated));
+  }
+
+  return (
+    <LoanContext.Provider value={{ loans, addLoan, returnLoan }}>
+      {children}
+    </LoanContext.Provider>
+  );
+}
+
+export function useLoans() {
+  return useContext(LoanContext);
+}

my-library/src/context/ReturnContext.js

@@ -0,0 +1,36 @@
+import { createContext, useContext, useState } from 'react';
+
+const ReturnContext = createContext(null);
+
+export function ReturnProvider({ children }) {
+  const [returns, setReturns] = useState(() => {
+    const saved = localStorage.getItem('returns');
+    return saved ? JSON.parse(saved) : [];
+  });
+
+  function addReturn(bookId, bookTitle, customerPhone, reason) {
+    const bookReturn = {
+      returnId: crypto.randomUUID(),
+      bookId,
+      bookTitle,
+      customerPhone,
+      reason,
+      status: 'PROCESSED',
+      returnedAt: new Date().toISOString(),
+    };
+    const updated = [...returns, bookReturn];
+    setReturns(updated);
+    localStorage.setItem('returns', JSON.stringify(updated));
+    return bookReturn;
+  }
+
+  return (
+    <ReturnContext.Provider value={{ returns, addReturn }}>
+      {children}
+    </ReturnContext.Provider>
+  );
+}
+
+export function useReturns() {
+  return useContext(ReturnContext);
+}

my-library/src/context/ReviewContext.js

@@ -0,0 +1,40 @@
+import { createContext, useContext, useState } from 'react';
+
+const ReviewContext = createContext(null);
+
+export function ReviewProvider({ children }) {
+  const [reviews, setReviews] = useState(() => {
+    const saved = localStorage.getItem('reviews');
+    return saved ? JSON.parse(saved) : [];
+  });
+
+  function addReview(bookId, bookTitle, username, rating, comment) {
+    const review = {
+      reviewId: crypto.randomUUID(),
+      bookId,
+      bookTitle,
+      username,
+      rating,
+      comment,
+      createdAt: new Date().toISOString(),
+    };
+    const updated = [...reviews, review];
+    setReviews(updated);
+    localStorage.setItem('reviews', JSON.stringify(updated));
+    return review;
+  }
+
+  function getReviewsByBook(bookId) {
+    return reviews.filter(r => String(r.bookId) === String(bookId));
+  }
+
+  return (
+    <ReviewContext.Provider value={{ reviews, addReview, getReviewsByBook }}>
+      {children}
+    </ReviewContext.Provider>
+  );
+}
+
+export function useReviews() {
+  return useContext(ReviewContext);
+}

my-library/src/context/SubscriptionContext.js

@@ -0,0 +1,50 @@
+import { createContext, useContext, useState } from 'react';
+
+const SubscriptionContext = createContext(null);
+
+const PLANS = [
+  { id: 'basic', name: 'Basic', price: 9.99, description: '2 livres par mois' },
+  { id: 'standard', name: 'Standard', price: 14.99, description: '5 livres par mois' },
+  { id: 'premium', name: 'Premium', price: 24.99, description: 'Livres illimités par mois' },
+];
+
+export { PLANS };
+
+export function SubscriptionProvider({ children }) {
+  const [subscription, setSubscription] = useState(() => {
+    const saved = localStorage.getItem('subscription');
+    return saved ? JSON.parse(saved) : null;
+  });
+
+  function subscribe(planId, phoneNumber) {
+    const plan = PLANS.find(p => p.id === planId);
+    const newSubscription = {
+      subscriptionId: crypto.randomUUID(),
+      planId,
+      planName: plan.name,
+      price: plan.price,
+      phoneNumber,
+      status: 'ACTIVE',
+      startDate: new Date().toISOString(),
+    };
+    setSubscription(newSubscription);
+    localStorage.setItem('subscription', JSON.stringify(newSubscription));
+    return newSubscription;
+  }
+
+  function cancelSubscription() {
+    const updated = { ...subscription, status: 'CANCELLED' };
+    setSubscription(updated);
+    localStorage.setItem('subscription', JSON.stringify(updated));
+  }
+
+  return (
+    <SubscriptionContext.Provider value={{ subscription, subscribe, cancelSubscription, PLANS }}>
+      {children}
+    </SubscriptionContext.Provider>
+  );
+}
+
+export function useSubscription() {
+  return useContext(SubscriptionContext);
+}

my-library/src/index.js

@@ -3,6 +3,11 @@ import ReactDOM from 'react-dom/client';
 import { BrowserRouter } from 'react-router-dom';
 import { AuthProvider } from './context/AuthContext';
 import { ReservationProvider } from './context/ReservationContext';
+import { ReviewProvider } from './context/ReviewContext';
+import { ReturnProvider } from './context/ReturnContext';
+import { SubscriptionProvider } from './context/SubscriptionContext';
+import { LoanProvider } from './context/LoanContext';
+import { GroupOrderProvider } from './context/GroupOrderContext';
 import App from './App';
 import './styles/global.css';
 
@@ -12,7 +17,17 @@ root.render(
     <BrowserRouter>
       <AuthProvider>
         <ReservationProvider>
-          <App />
+          <ReviewProvider>
+            <ReturnProvider>
+              <SubscriptionProvider>
+                <LoanProvider>
+                  <GroupOrderProvider>
+                    <App />
+                  </GroupOrderProvider>
+                </LoanProvider>
+              </SubscriptionProvider>
+            </ReturnProvider>
+          </ReviewProvider>
         </ReservationProvider>
       </AuthProvider>
     </BrowserRouter>

my-library/src/pages/BookDetail.jsx

@@ -3,10 +3,17 @@ import { useParams, Link } from 'react-router-dom';
 import { getBookById } from '../api/books';
 import { useAuth } from '../context/AuthContext';
 import { useReservations } from '../context/ReservationContext';
+import { useReviews } from '../context/ReviewContext';
+import { useSubscription } from '../context/SubscriptionContext';
 
 export default function BookDetail() {
   const { user } = useAuth();
-  const { addReservation } = useReservations();
+  const { subscription } = useSubscription();
+  const { addReservation, reservations } = useReservations();
+  const { addReview, getReviewsByBook } = useReviews();
+  const [rating, setRating] = useState(5);
+  const [comment, setComment] = useState('');
+  const [reviewStatus, setReviewStatus] = useState(null);
   const { bookId } = useParams();
   const [book, setBook] = useState(null);
   const [loading, setLoading] = useState(true);
@@ -23,6 +30,14 @@ export default function BookDetail() {
     setPhoneNumber('');
   }
 
+  function handleReview(e) {
+    e.preventDefault();
+    addReview(book.isbn, book.title, user.username, Number(rating), comment);
+    setReviewStatus({ success: true, message: 'Avis publié avec succès !' });
+    setComment('');
+    setRating(5);
+  }
+
   if (loading) return <main><p>Chargement…</p></main>;
   if (error) return <main><p>{error}</p><Link to="/books">← Retour au catalogue</Link></main>;
 
@@ -40,27 +55,104 @@ export default function BookDetail() {
       <p>Catégories : {book.categories?.join(', ')}</p>
       {book.description && <p>{book.description}</p>}
 
-      {user?.role === 'user' && <section>
+      <section>
-        <h2>Réserver ce livre</h2>
+        <h2>Avis des lecteurs</h2>
-        <form onSubmit={handleReservation}>
+        {getReviewsByBook(book.isbn).length === 0 ? (
-          <label>
+          <p>Aucun avis pour le moment.</p>
-            Numéro de téléphone :
+        ) : (
-            <input
+          <ul>
-              type="tel"
+            {getReviewsByBook(book.isbn).map(r => (
-              value={phoneNumber}
+              <li key={r.reviewId}>
-              onChange={(e) => setPhoneNumber(e.target.value)}
+                <strong>{r.username}</strong> — {'*'.repeat(r.rating)}
-              placeholder="0612345678"
+                <br />
-              required
+                {r.comment}
-            />
+                <br />
-          </label>
+                <small>{new Date(r.createdAt).toLocaleDateString('fr-FR')}</small>
-          <button type="submit">Réserver</button>
+              </li>
-        </form>
+            ))}
-        {reservationStatus && (
+          </ul>
-          <p style={{ color: reservationStatus.success ? 'green' : 'red' }}>
+        )}
-            {reservationStatus.message}
+        {user?.role === 'user' && (
+          <form onSubmit={handleReview}>
+            <h3>Laisser un avis</h3>
+            <label>
+              Note :
+              <select value={rating} onChange={e => setRating(e.target.value)}>
+                <option value={1}>*</option>
+                <option value={2}>**</option>
+                <option value={3}>***</option>
+                <option value={4}>****</option>
+                <option value={5}>*****</option>
+              </select>
+            </label>
+            <label>
+              Commentaire :
+              <textarea value={comment} onChange={e => setComment(e.target.value)} required />
+            </label>
+            <button type="submit">Publier l'avis</button>
+          </form>
+        )}
+        {reviewStatus && (
+          <p style={{ color: reviewStatus.success ? 'green' : 'red' }}>
+            {reviewStatus.message}
           </p>
         )}
-      </section>}
+      </section>
+
+      {user?.role === 'user' && (
+        <section>
+          <h2>Réserver ce livre</h2>
+          {!subscription || subscription.status !== 'ACTIVE' ? (
+            <p>
+              Vous devez avoir un abonnement actif pour réserver un livre.{' '}
+              <Link to="/subscription">S'abonner</Link>
+            </p>
+          ) : (() => {
+            const QUOTAS = { basic: 2, standard: 5, premium: Infinity };
+            const quota = QUOTAS[subscription.planId];
+            const thisMonthStart = new Date();
+            thisMonthStart.setDate(1);
+            thisMonthStart.setHours(0, 0, 0, 0);
+            const usedThisMonth = reservations.filter(r =>
+              new Date(r.reservedAt) >= thisMonthStart
+            ).length;
+            const remaining = quota - usedThisMonth;
+
+            if (remaining <= 0) {
+              return (
+                <p style={{ color: 'orange' }}>
+                  Vous avez atteint votre quota de {quota} réservation(s) ce mois-ci.
+                  <Link to="/subscription"> Passer au plan supérieur</Link>
+                </p>
+              );
+            }
+
+            return (
+              <>
+                <p>Réservations restantes ce mois : <strong>{remaining === Infinity ? 'illimitées' : remaining}</strong></p>
+                <form onSubmit={handleReservation}>
+                  <label>
+                    Numéro de téléphone :
+                    <input
+                      type="tel"
+                      value={phoneNumber}
+                      onChange={(e) => setPhoneNumber(e.target.value)}
+                      placeholder="0612345678"
+                      required
+                    />
+                  </label>
+                  <button type="submit">Réserver</button>
+                </form>
+                {reservationStatus && (
+                  <p style={{ color: reservationStatus.success ? 'green' : 'red' }}>
+                    {reservationStatus.message}
+                  </p>
+                )}
+              </>
+            );
+          })()}
+        </section>
+      )}
     </main>
   );
 }

my-library/src/pages/GroupOrders.jsx

@@ -0,0 +1,167 @@
+import { useState } from 'react';
+import { useGroupOrders } from '../context/GroupOrderContext';
+import { useAuth } from '../context/AuthContext';
+
+export default function GroupOrders() {
+  const { groups, createGroup, addOrderToGroup, closeGroup } = useGroupOrders();
+  const { user } = useAuth();
+
+  const [creatorPhone, setCreatorPhone] = useState('');
+  const [joinGroupId, setJoinGroupId] = useState('');
+  const [joinForm, setJoinForm] = useState({ phoneNumber: '', bookId: '', bookTitle: '', quantity: 1 });
+  const [joinStatus, setJoinStatus] = useState({});
+  const [createStatus, setCreateStatus] = useState(null);
+
+  function handleCreateGroup(e) {
+    e.preventDefault();
+    const group = createGroup(creatorPhone);
+    setCreateStatus(`Groupe créé ! ID : ${group.id}`);
+    setCreatorPhone('');
+  }
+
+  function handleJoinGroup(e) {
+    e.preventDefault();
+    const group = groups.find(g => g.id === joinGroupId);
+    if (!group) {
+      setJoinStatus(prev => ({ ...prev, [joinGroupId]: 'Groupe introuvable.' }));
+      return;
+    }
+    if (group.status === 'CLOSED') {
+      setJoinStatus(prev => ({ ...prev, [joinGroupId]: 'Ce groupe est fermé.' }));
+      return;
+    }
+    addOrderToGroup(joinGroupId, joinForm.phoneNumber, joinForm.bookId, joinForm.bookTitle, joinForm.quantity);
+    setJoinStatus(prev => ({ ...prev, [joinGroupId]: 'Commande ajoutée au groupe !' }));
+    setJoinForm({ phoneNumber: '', bookId: '', bookTitle: '', quantity: 1 });
+  }
+
+  const openGroups = groups.filter(g => g.status === 'OPEN');
+  const closedGroups = groups.filter(g => g.status === 'CLOSED');
+
+  return (
+    <main>
+      <h1>Commandes groupées</h1>
+
+      <section>
+        <h2>Créer un groupe</h2>
+        <form onSubmit={handleCreateGroup}>
+          <label>
+            Votre téléphone :
+            <input
+              type="tel"
+              value={creatorPhone}
+              onChange={e => setCreatorPhone(e.target.value)}
+              placeholder="0612345678"
+              required
+            />
+          </label>
+          <button type="submit">Créer un groupe</button>
+        </form>
+        {createStatus && <p style={{ color: 'green' }}>{createStatus}</p>}
+      </section>
+
+      <section>
+        <h2>Rejoindre un groupe</h2>
+        <form onSubmit={handleJoinGroup}>
+          <label>
+            ID du groupe :
+            <input
+              value={joinGroupId}
+              onChange={e => setJoinGroupId(e.target.value)}
+              placeholder="Collez l'ID du groupe ici"
+              required
+            />
+          </label>
+          <label>
+            Votre téléphone :
+            <input
+              type="tel"
+              value={joinForm.phoneNumber}
+              onChange={e => setJoinForm(prev => ({ ...prev, phoneNumber: e.target.value }))}
+              placeholder="0612345678"
+              required
+            />
+          </label>
+          <label>
+            ISBN du livre :
+            <input
+              value={joinForm.bookId}
+              onChange={e => setJoinForm(prev => ({ ...prev, bookId: e.target.value }))}
+              placeholder="9782070361038"
+              required
+            />
+          </label>
+          <label>
+            Titre du livre :
+            <input
+              value={joinForm.bookTitle}
+              onChange={e => setJoinForm(prev => ({ ...prev, bookTitle: e.target.value }))}
+              placeholder="Nom du livre"
+              required
+            />
+          </label>
+          <label>
+            Quantité :
+            <input
+              type="number"
+              min="1"
+              value={joinForm.quantity}
+              onChange={e => setJoinForm(prev => ({ ...prev, quantity: e.target.value }))}
+              required
+            />
+          </label>
+          <button type="submit">Rejoindre</button>
+        </form>
+        {joinStatus[joinGroupId] && (
+          <p style={{ color: joinStatus[joinGroupId].includes('introuvable') || joinStatus[joinGroupId].includes('fermé') ? 'red' : 'green' }}>
+            {joinStatus[joinGroupId]}
+          </p>
+        )}
+      </section>
+
+      <section>
+        <h2>Groupes ouverts ({openGroups.length})</h2>
+        {openGroups.length === 0 ? (
+          <p>Aucun groupe ouvert.</p>
+        ) : (
+          <ul>
+            {openGroups.map(g => (
+              <li key={g.id}>
+                <strong>Groupe {g.id.slice(0, 8)}…</strong>
+                <br />
+                Créé par : {g.creatorPhone}
+                <br />
+                Créé le : {new Date(g.createdAt).toLocaleDateString('fr-FR')}
+                <br />
+                Participants : {g.orders.length}
+                {g.orders.length > 0 && (
+                  <ul>
+                    {g.orders.map(o => (
+                      <li key={o.orderId}>
+                        {o.phoneNumber} , {o.bookTitle} (x{o.quantity})
+                      </li>
+                    ))}
+                  </ul>
+                )}
+                <button onClick={() => closeGroup(g.id)}>Fermer le groupe</button>
+              </li>
+            ))}
+          </ul>
+        )}
+      </section>
+
+      {closedGroups.length > 0 && (
+        <section>
+          <h2>Groupes fermés ({closedGroups.length})</h2>
+          <ul>
+            {closedGroups.map(g => (
+              <li key={g.id}>
+                <strong>Groupe {g.id.slice(0, 8)}…</strong> , {g.orders.length} commande(s) , <small>Fermé ✓</small>
+              </li>
+            ))}
+          </ul>
+        </section>
+      )}
+    </main>
+  );
+}

my-library/src/pages/Loans.jsx

@@ -0,0 +1,54 @@
+import { useLoans } from '../context/LoanContext';
+
+export default function Loans() {
+  const { loans, returnLoan } = useLoans();
+
+  const activeLoans = loans.filter(l => l.status === 'ACTIVE');
+  const returnedLoans = loans.filter(l => l.status === 'RETURNED');
+
+  return (
+    <main>
+      <h1>Mes prêts</h1>
+
+      <section>
+        <h2>Prêts en cours ({activeLoans.length})</h2>
+        {activeLoans.length === 0 ? (
+          <p>Aucun prêt en cours.</p>
+        ) : (
+          <ul>
+            {activeLoans.map(l => (
+              <li key={l.loanId}>
+                <strong>{l.bookTitle}</strong> — {l.bookAuthor}
+                <br />
+                Prêté à : {l.borrowerPhone}
+                <br />
+                À rendre avant le : {new Date(l.dueDate).toLocaleDateString('fr-FR')}
+                <br />
+                Prêté le : {new Date(l.loanedAt).toLocaleDateString('fr-FR')}
+                <br />
+                <button onClick={() => returnLoan(l.loanId)}>Marquer comme rendu</button>
+              </li>
+            ))}
+          </ul>
+        )}
+      </section>
+
+      {returnedLoans.length > 0 && (
+        <section>
+          <h2>Prêts terminés ({returnedLoans.length})</h2>
+          <ul>
+            {returnedLoans.map(l => (
+              <li key={l.loanId}>
+                <strong>{l.bookTitle}</strong> — {l.bookAuthor}
+                <br />
+                Prêté à : {l.borrowerPhone}
+                <br />
+                <small>Rendu ✓</small>
+              </li>
+            ))}
+          </ul>
+        </section>
+      )}
+    </main>
+  );
+}

my-library/src/pages/Orders.jsx

@@ -1,3 +1,91 @@
+import { useState } from 'react';
+import { createOrder } from '../api/orders';
+
 export default function Orders() {
-  return <main><h1>Mes commandes</h1></main>;
+  const [customerId, setCustomerId] = useState('');
-}
+  const [paymentMethod, setPaymentMethod] = useState('CREDIT_CARD');
+  const [address, setAddress] = useState({ street: '', city: '', postalCode: '', country: '' });
+  const [lines, setLines] = useState([{ bookId: '', quantity: 1 }]);
+  const [message, setMessage] = useState(null);
+  const [submitting, setSubmitting] = useState(false);
+
+  function handleAddressChange(e) {
+    const { name, value } = e.target;
+    setAddress((prev) => ({ ...prev, [name]: value }));
+  }
+
+  function handleLineChange(index, field, value) {
+    setLines((prev) => prev.map((line, i) => (i === index ? { ...line, [field]: value } : line)));
+  }
+  function addLine() {
+    setLines((prev) => [...prev, { bookId: '', quantity: 1 }]);
+  }
+  function removeLine(index) {
+    setLines((prev) => prev.filter((_, i) => i !== index));
+  }
+
+  function handleSubmit(e) {
+    e.preventDefault();
+    setSubmitting(true);
+    setMessage(null);
+
+    const payload = {
+      customerId,
+      paymentMethod,
+      address,
+      orderLineDtos: lines.map((line) => ({
+        bookId: Number(line.bookId),
+        quantity: Number(line.quantity),
+      })),
+    };
+
+    createOrder(payload)
+      .then((response) => setMessage('Commande créée'))
+      .catch((error) => {
+        console.error(error);
+        setMessage(error.response?.data?.message || 'Erreur lors de la commande.');
+      })
+      .finally(() => setSubmitting(false));
+  }
+
+  return (
+    <main>
+      <h1>Passer une commande</h1>
+      <form onSubmit={handleSubmit}>
+        <label>ID client
+          <input value={customerId} onChange={(e) => setCustomerId(e.target.value)} required />
+        </label>
+
+        <h2>Livres</h2>
+        {lines.map((line, index) => (
+          <div key={index}>
+            <input type="number" placeholder="ISBN du livre" value={line.bookId}
+              onChange={(e) => handleLineChange(index, 'bookId', e.target.value)} required />
+            <input type="number" placeholder="Quantité" value={line.quantity}
+              onChange={(e) => handleLineChange(index, 'quantity', e.target.value)} required />
+            {lines.length > 1 && (
+              <button type="button" onClick={() => removeLine(index)}>Retirer</button>
+            )}
+          </div>
+        ))}
+        <button type="button" onClick={addLine}>+ Ajouter un livre</button>
+
+        <h2>Adresse de livraison</h2>
+        <input name="street" placeholder="Rue" value={address.street} onChange={handleAddressChange} required />
+        <input name="city" placeholder="Ville" value={address.city} onChange={handleAddressChange} required />
+        <input name="postalCode" placeholder="Code postal" value={address.postalCode} onChange={handleAddressChange} required />
+        <input name="country" placeholder="Pays" value={address.country} onChange={handleAddressChange} required />
+
+        <h2>Paiement</h2>
+        <select value={paymentMethod} onChange={(e) => setPaymentMethod(e.target.value)}>
+          <option value="CREDIT_CARD">Carte bancaire</option>
+        </select>
+
+        <button type="submit" disabled={submitting}>
+          {submitting ? 'Envoi…' : 'Valider la commande'}
+        </button>
+      </form>
+      {message && <p>{message}</p>}
+    </main>
+  );
+}

my-library/src/pages/Reservations.jsx

@@ -1,8 +1,32 @@
+import { useState } from 'react';
 import { useReservations } from '../context/ReservationContext';
+import { useLoans } from '../context/LoanContext';
 import { Link } from 'react-router-dom';
 
 export default function Reservations() {
   const { reservations, cancelReservation } = useReservations();
+  const { addLoan } = useLoans();
+  const [loanForms, setLoanForms] = useState({});
+  const [loanStatuses, setLoanStatuses] = useState({});
+
+  function handleLoanChange(reservationId, field, value) {
+    setLoanForms(prev => ({
+      ...prev,
+      [reservationId]: { ...prev[reservationId], [field]: value }
+    }));
+  }
+
+  function handleLoan(e, reservation) {
+    e.preventDefault();
+    const form = loanForms[reservation.reservationId] || {};
+    addLoan(
+      { isbn: reservation.bookId, title: reservation.bookTitle, author: reservation.bookAuthor },
+      form.borrowerPhone,
+      form.dueDate
+    );
+    setLoanStatuses(prev => ({ ...prev, [reservation.reservationId]: 'Prêt enregistré avec succès !' }));
+    setLoanForms(prev => ({ ...prev, [reservation.reservationId]: {} }));
+  }
 
   if (reservations.length === 0) {
     return (
@@ -29,6 +53,36 @@ export default function Reservations() {
             Statut : {r.status}
             <br />
             <button onClick={() => cancelReservation(r.reservationId)}>Annuler</button>
+
+            <details>
+              <summary>Prêter ce livre à un autre lecteur</summary>
+              <form onSubmit={e => handleLoan(e, r)}>
+                <label>
+                  Téléphone de l'emprunteur :
+                  <input
+                    type="tel"
+                    value={loanForms[r.reservationId]?.borrowerPhone || ''}
+                    onChange={e => handleLoanChange(r.reservationId, 'borrowerPhone', e.target.value)}
+                    placeholder="0612345678"
+                    required
+                  />
+                </label>
+                <label>
+                  Date de retour prévue :
+                  <input
+                    type="date"
+                    value={loanForms[r.reservationId]?.dueDate || ''}
+                    onChange={e => handleLoanChange(r.reservationId, 'dueDate', e.target.value)}
+                    min={new Date().toISOString().split('T')[0]}
+                    required
+                  />
+                </label>
+                <button type="submit">Prêter</button>
+              </form>
+              {loanStatuses[r.reservationId] && (
+                <p style={{ color: 'green' }}>{loanStatuses[r.reservationId]}</p>
+              )}
+            </details>
           </li>
         ))}
       </ul>

my-library/src/pages/Returns.jsx

@@ -0,0 +1,96 @@
+import { useState } from 'react';
+import { useReturns } from '../context/ReturnContext';
+import { getBooks } from '../api/books';
+import { useEffect } from 'react';
+
+export default function Returns() {
+  const { returns, addReturn } = useReturns();
+  const [books, setBooks] = useState([]);
+  const [form, setForm] = useState({ bookId: '', customerPhone: '', reason: '' });
+  const [message, setMessage] = useState(null);
+
+  useEffect(() => {
+    getBooks(0, 100).then(res => setBooks(res.data.content)).catch(console.error);
+  }, []);
+
+  function handleChange(e) {
+    const { name, value } = e.target;
+    setForm(f => ({ ...f, [name]: value }));
+  }
+
+  function handleSubmit(e) {
+    e.preventDefault();
+    const book = books.find(b => String(b.isbn) === String(form.bookId));
+    const bookTitle = book ? book.title : form.bookId;
+    addReturn(form.bookId, bookTitle, form.customerPhone, form.reason);
+    setMessage({ success: true, text: 'Retour enregistré avec succès !' });
+    setForm({ bookId: '', customerPhone: '', reason: '' });
+  }
+
+  return (
+    <main>
+      <h1>Gestion des retours</h1>
+
+      <section>
+        <h2>Enregistrer un retour</h2>
+        <form onSubmit={handleSubmit}>
+          <label>
+            Livre :
+            <select name="bookId" value={form.bookId} onChange={handleChange} required>
+              <option value="">-- Choisir un livre --</option>
+              {books.map(b => (
+                <option key={b.isbn} value={b.isbn}>{b.title} — {b.author}</option>
+              ))}
+            </select>
+          </label>
+          <label>
+            Téléphone du client :
+            <input
+              name="customerPhone"
+              type="tel"
+              value={form.customerPhone}
+              onChange={handleChange}
+              placeholder="0612345678"
+              required
+            />
+          </label>
+          <label>
+            Motif :
+            <textarea
+              name="reason"
+              value={form.reason}
+              onChange={handleChange}
+              placeholder="Motif du retour..."
+              required
+            />
+          </label>
+          <button type="submit">Enregistrer le retour</button>
+        </form>
+        {message && <p style={{ color: message.success ? 'green' : 'red' }}>{message.text}</p>}
+      </section>
+
+      <section>
+        <h2>Historique des retours</h2>
+        {returns.length === 0 ? (
+          <p>Aucun retour enregistré.</p>
+        ) : (
+          <ul>
+            {returns.map(r => (
+              <li key={r.returnId}>
+                <strong>{r.bookTitle}</strong>
+                <br />
+                Client : {r.customerPhone}
+                <br />
+                Motif : {r.reason}
+                <br />
+                Statut : {r.status}
+                <br />
+                <small>{new Date(r.returnedAt).toLocaleDateString('fr-FR')}</small>
+              </li>
+            ))}
+          </ul>
+        )}
+      </section>
+    </main>
+  );
+}

my-library/src/pages/Subscription.jsx

@@ -0,0 +1,74 @@
+import { useState } from 'react';
+import { useSubscription } from '../context/SubscriptionContext';
+
+export default function Subscription() {
+  const { subscription, subscribe, cancelSubscription, PLANS } = useSubscription();
+  const [selectedPlan, setSelectedPlan] = useState('basic');
+  const [phoneNumber, setPhoneNumber] = useState('');
+  const [message, setMessage] = useState(null);
+
+  function handleSubscribe(e) {
+    e.preventDefault();
+    subscribe(selectedPlan, phoneNumber);
+    setMessage({ success: true, text: 'Abonnement créé avec succès !' });
+    setPhoneNumber('');
+  }
+
+  function handleCancel() {
+    cancelSubscription();
+    setMessage({ success: false, text: 'Abonnement annulé.' });
+  }
+
+  return (
+    <main>
+      <h1>Mon abonnement</h1>
+
+      {subscription && subscription.status === 'ACTIVE' ? (
+        <section>
+          <h2>Abonnement actif</h2>
+          <p>Plan : <strong>{subscription.planName}</strong></p>
+          <p>Prix : <strong>{subscription.price} € / mois</strong></p>
+          <p>Téléphone : {subscription.phoneNumber}</p>
+          <p>Depuis le : {new Date(subscription.startDate).toLocaleDateString('fr-FR')}</p>
+          <p>Statut : <strong style={{ color: 'green' }}>{subscription.status}</strong></p>
+          <button onClick={handleCancel}>Annuler l'abonnement</button>
+        </section>
+      ) : (
+        <section>
+          <h2>Choisir un abonnement</h2>
+          <form onSubmit={handleSubscribe}>
+            <div>
+              {PLANS.map(plan => (
+                <label key={plan.id} style={{ display: 'block', marginBottom: '8px' }}>
+                  <input
+                    type="radio"
+                    name="plan"
+                    value={plan.id}
+                    checked={selectedPlan === plan.id}
+                    onChange={() => setSelectedPlan(plan.id)}
+                  />
+                  {' '}<strong>{plan.name}</strong> , {plan.price} € / mois , {plan.description}
+                </label>
+              ))}
+            </div>
+            <label>
+              Numéro de téléphone :
+              <input
+                type="tel"
+                value={phoneNumber}
+                onChange={e => setPhoneNumber(e.target.value)}
+                placeholder="0612345678"
+                required
+              />
+            </label>
+            <button type="submit">S'abonner</button>
+          </form>
+        </section>
+      )}
+
+      {message && (
+        <p style={{ color: message.success ? 'green' : 'red' }}>{message.text}</p>
+      )}
+    </main>
+  );
+}

mylibrary/README.md

@@ -0,0 +1,78 @@
+# mylibrary — back-end Java (méthode BDD)
+
+Back-end du projet **2026-DEV-BUT3**. Reproduit, en Java pur, le cœur métier
+de l'API consommée par le front React `my-library/`.
+
+## Méthode
+
+Conformément au cours `maintenanceApplicativeCours1.pdf` (Behavior-Driven
+Development), pour chaque comportement on :
+
+1. Écrit le scénario attendu (en Gherkin / `.feature` ou en `@DisplayName` JUnit)
+2. Écrit le test qui le vérifie
+3. Implémente le code qui fait passer le test
+
+## Structure (calquée sur le module `customer` fourni par le prof)
+
+```
+src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/
+├─ customer/        Module fourni par l'enseignant (intact)
+│  ├─ CustomerInfo.java   record d'entrée
+│  ├─ CustomerDTO.java    DTO de sortie
+│  ├─ entity/             Customer (objet métier, règles fidélité)
+│  ├─ exception/          Exceptions métier
+│  ├─ converter/          Mapping Info <-> entity <-> DTO
+│  ├─ validator/          Règles de validation
+│  ├─ repository/         Stockage en mémoire (List)
+│  └─ usecase/            Cas d'usage (orchestration)
+└─ book/             Module développé en miroir (notre travail)
+   └─ … (mêmes sous-paquets, même découpage)
+
+src/test/java/.../mylibrary/
+├─ customer/         Tests JUnit fournis par l'enseignant
+├─ book/             Tests JUnit que nous avons écrits
+└─ features/
+   ├─ RunCucumberTest.java         (du prof, intact)
+   ├─ client/CustomerSteps.java    (du prof, intact)
+   ├─ book/BookSteps.java          (notre travail)
+   └─ resources/features/
+      ├─ client.feature            (du prof, intact)
+      └─ book.feature              (notre travail)
+```
+
+## Dépendances
+
+Strictement les mêmes que dans le template du prof :
+
+- JUnit 5 (jupiter-api, params, engine + platform-suite, platform-engine, platform-launcher)
+- Mockito (core, junit-jupiter)
+- Cucumber (cucumber-java, cucumber-junit-platform-engine)
+- Lombok
+
+## Build & test
+
+Pré-requis : **JDK 21** + **Maven 3.9+**
+
+```bash
+mvn -f mylibrary test
+```
+
+Cette commande exécute :
+
+- les tests unitaires JUnit (entity, validator, converter, repository, usecase, exceptions)
+- les scénarios Cucumber (`client.feature` + `book.feature`) via `RunCucumberTest`
+
+## Périmètre couvert
+
+Conformément à la consigne (« reproduire le strict nécessaire pour démontrer
+la maîtrise »), l'API se limite aux deux domaines présents dans le swagger
+qui structurent l'app React :
+
+- **Catalogue** (`book`) : enregistrer, consulter par ISBN, lister tous les livres,
+  refuser ISBN dupliqué, refuser un livre invalide, gérer le stock.
+- **Comptes clients** (`customer`) : enregistrer, consulter par téléphone, mettre
+  à jour, supprimer, ajouter / retirer des points de fidélité (module fourni).
+
+L'exposition HTTP réelle utilisée par les développeurs front est l'API du prof
+(`mylibrary-0.0.1-SNAPSHOT.jar`) ; ce module sert à démontrer la maîtrise
+de la **conception métier en BDD/TDD**.

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/BookDTO.java

@@ -0,0 +1,22 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Category;
+import java.time.LocalDate;
+import java.util.List;
+import lombok.Builder;
+import lombok.Getter;
+
+@Builder
+@Getter
+public class BookDTO {
+  private final long isbn;
+  private final String title;
+  private final String author;
+  private final String publisher;
+  private final LocalDate publicationDate;
+  private final double price;
+  private final int quantity;
+  private final List<Category> categories;
+  private final String description;
+  private final String language;
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/converter/BookConverter.java

@@ -0,0 +1,42 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.converter;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookDTO;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Book;
+
+public final class BookConverter {
+
+  private BookConverter() {
+
+  }
+
+  public static Book toDomain(BookInfo book) {
+    return Book.builder()
+        .isbn(book.isbn())
+        .title(book.title())
+        .author(book.author())
+        .publisher(book.publisher())
+        .publicationDate(book.publicationDate())
+        .price(book.price())
+        .quantity(book.quantity())
+        .categories(book.categories())
+        .description(book.description())
+        .language(book.language())
+        .build();
+  }
+
+  public static BookDTO toDTO(Book book) {
+    return BookDTO.builder()
+        .isbn(book.getIsbn())
+        .title(book.getTitle())
+        .author(book.getAuthor())
+        .publisher(book.getPublisher())
+        .publicationDate(book.getPublicationDate())
+        .price(book.getPrice())
+        .quantity(book.getQuantity())
+        .categories(book.getCategories())
+        .description(book.getDescription())
+        .language(book.getLanguage())
+        .build();
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/BookAlreadyExistsException.java

@@ -0,0 +1,13 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import java.text.MessageFormat;
+
+public class BookAlreadyExistsException extends Exception {
+
+  public static final String A_BOOK_WITH_ISBN_ALREADY_EXISTS_MESSAGE = "A book with isbn {0} already exists";
+
+  public BookAlreadyExistsException(long isbn) {
+    // ISBN passe en String pour ne pas que MessageFormat ajoute le separateur de milliers
+    super(MessageFormat.format(A_BOOK_WITH_ISBN_ALREADY_EXISTS_MESSAGE, String.valueOf(isbn)));
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/BookNotFoundException.java

@@ -0,0 +1,13 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import java.text.MessageFormat;
+
+public class BookNotFoundException extends Exception {
+
+  public static final String THE_BOOK_WITH_ISBN_DOES_NOT_EXIST_MESSAGE = "The book with isbn {0} does not exist";
+
+  public BookNotFoundException(long isbn) {
+    // ISBN passe en String pour ne pas que MessageFormat ajoute le separateur de milliers
+    super(MessageFormat.format(THE_BOOK_WITH_ISBN_DOES_NOT_EXIST_MESSAGE, String.valueOf(isbn)));
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/IllegalBookQuantityException.java

@@ -0,0 +1,12 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import java.text.MessageFormat;
+
+public class IllegalBookQuantityException extends Exception {
+
+  public static final String CANNOT_REMOVE_STOCK = "Cannot remove {0} units from {1} units in stock";
+
+  public IllegalBookQuantityException(int needed, int actual) {
+    super(MessageFormat.format(CANNOT_REMOVE_STOCK, needed, actual));
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/NotValidBookException.java

@@ -0,0 +1,8 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+public class NotValidBookException extends Exception {
+
+  public NotValidBookException(String message) {
+    super(message);
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/repository/BookRepository.java

@@ -0,0 +1,42 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.repository;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Book;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+public final class BookRepository {
+
+  private final List<Book> books = new ArrayList<>();
+
+  public List<Book> findAll() {
+    return books;
+  }
+
+  public void deleteAll() {
+    books.clear();
+  }
+
+  public Book save(Book book) {
+    Optional<Book> existing = findByIsbn(book.getIsbn());
+    existing.ifPresent(books::remove);
+    books.add(book);
+    return book;
+  }
+
+  public Optional<Book> findByIsbn(long isbn) {
+    return books.stream()
+        .filter(b -> b.getIsbn() == isbn)
+        .findFirst();
+  }
+
+  public boolean existsByIsbn(long isbn) {
+    return books.stream().anyMatch(b -> b.getIsbn() == isbn);
+  }
+
+  public void delete(Book book) {
+    books.remove(book);
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/usecase/BookUseCase.java

@@ -0,0 +1,46 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.usecase;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookDTO;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.converter.BookConverter;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Book;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.BookAlreadyExistsException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.BookNotFoundException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.NotValidBookException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.repository.BookRepository;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.validator.BookValidator;
+import java.util.List;
+import java.util.Optional;
+
+public final class BookUseCase {
+
+  private final BookRepository bookRepository;
+
+  public BookUseCase(BookRepository bookRepository) {
+    this.bookRepository = bookRepository;
+  }
+
+  public long registerBook(BookInfo bookInfo) throws NotValidBookException, BookAlreadyExistsException {
+    BookValidator.validate(bookInfo);
+    if (bookRepository.existsByIsbn(bookInfo.isbn())) {
+      throw new BookAlreadyExistsException(bookInfo.isbn());
+    }
+    Book toRegister = BookConverter.toDomain(bookInfo);
+    Book registered = bookRepository.save(toRegister);
+    return registered.getIsbn();
+  }
+
+  public BookDTO getBookByIsbn(long isbn) throws BookNotFoundException {
+    Optional<Book> optional = bookRepository.findByIsbn(isbn);
+    if (optional.isEmpty()) {
+      throw new BookNotFoundException(isbn);
+    }
+    return BookConverter.toDTO(optional.get());
+  }
+
+  public List<BookDTO> getAllBooks() {
+    return bookRepository.findAll().stream()
+        .map(BookConverter::toDTO)
+        .toList();
+  }
+}

mylibrary/src/main/java/fr/iut_fbleau/but3/dev62/mylibrary/book/validator/BookValidator.java

@@ -0,0 +1,93 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.validator;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.NotValidBookException;
+
+public final class BookValidator {
+
+  public static final int TITLE_MAX_LENGTH = 255;
+
+  public static final String ISBN_MUST_BE_POSITIVE = "Isbn must be a positive number";
+  public static final String TITLE_CANNOT_BE_BLANK = "Title cannot be blank";
+  public static final String TITLE_TOO_LONG = "Title cannot exceed " + TITLE_MAX_LENGTH + " characters";
+  public static final String AUTHOR_CANNOT_BE_BLANK = "Author cannot be blank";
+  public static final String PUBLISHER_CANNOT_BE_BLANK = "Publisher cannot be blank";
+  public static final String PUBLICATION_DATE_REQUIRED = "Publication date is required";
+  public static final String PRICE_MUST_BE_POSITIVE = "Price must be strictly positive";
+  public static final String QUANTITY_MUST_BE_POSITIVE_OR_ZERO = "Quantity must be >= 0";
+  public static final String CATEGORIES_REQUIRED = "At least one category is required";
+  public static final String LANGUAGE_CANNOT_BE_BLANK = "Language cannot be blank";
+
+  private BookValidator() {
+
+  }
+
+  public static void validate(BookInfo book) throws NotValidBookException {
+    validateIsbn(book);
+    validateTitle(book);
+    validateAuthor(book);
+    validatePublisher(book);
+    validatePublicationDate(book);
+    validatePrice(book);
+    validateQuantity(book);
+    validateCategories(book);
+    validateLanguage(book);
+  }
+
+  private static void validateIsbn(BookInfo book) throws NotValidBookException {
+    if (book.isbn() <= 0) {
+      throw new NotValidBookException(ISBN_MUST_BE_POSITIVE);
+    }
+  }
+
+  private static void validateTitle(BookInfo book) throws NotValidBookException {
+    if (book.title() == null || book.title().isBlank()) {
+      throw new NotValidBookException(TITLE_CANNOT_BE_BLANK);
+    }
+    if (book.title().length() > TITLE_MAX_LENGTH) {
+      throw new NotValidBookException(TITLE_TOO_LONG);
+    }
+  }
+
+  private static void validateAuthor(BookInfo book) throws NotValidBookException {
+    if (book.author() == null || book.author().isBlank()) {
+      throw new NotValidBookException(AUTHOR_CANNOT_BE_BLANK);
+    }
+  }
+
+  private static void validatePublisher(BookInfo book) throws NotValidBookException {
+    if (book.publisher() == null || book.publisher().isBlank()) {
+      throw new NotValidBookException(PUBLISHER_CANNOT_BE_BLANK);
+    }
+  }
+
+  private static void validatePublicationDate(BookInfo book) throws NotValidBookException {
+    if (book.publicationDate() == null) {
+      throw new NotValidBookException(PUBLICATION_DATE_REQUIRED);
+    }
+  }
+
+  private static void validatePrice(BookInfo book) throws NotValidBookException {
+    if (book.price() <= 0) {
+      throw new NotValidBookException(PRICE_MUST_BE_POSITIVE);
+    }
+  }
+
+  private static void validateQuantity(BookInfo book) throws NotValidBookException {
+    if (book.quantity() < 0) {
+      throw new NotValidBookException(QUANTITY_MUST_BE_POSITIVE_OR_ZERO);
+    }
+  }
+
+  private static void validateCategories(BookInfo book) throws NotValidBookException {
+    if (book.categories() == null || book.categories().isEmpty()) {
+      throw new NotValidBookException(CATEGORIES_REQUIRED);
+    }
+  }
+
+  private static void validateLanguage(BookInfo book) throws NotValidBookException {
+    if (book.language() == null || book.language().isBlank()) {
+      throw new NotValidBookException(LANGUAGE_CANNOT_BE_BLANK);
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/converter/BookConverterTest.java

@@ -0,0 +1,86 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.converter;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookDTO;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Book;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Category;
+import java.time.LocalDate;
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookConverterTest {
+
+  @Nested
+  @DisplayName("toDomain() method tests")
+  class ToDomainTests {
+
+    @Test
+    @DisplayName("Should convert BookInfo to Book entity preserving all fields")
+    void testToDomain() {
+      BookInfo info = new BookInfo(
+          9780321125217L,
+          "DDD",
+          "Evans",
+          "Addison-Wesley",
+          LocalDate.of(2003, 8, 22),
+          54.99,
+          10,
+          List.of(Category.SCIENCE),
+          "desc",
+          "EN"
+      );
+
+      Book book = BookConverter.toDomain(info);
+
+      assertEquals(info.isbn(), book.getIsbn());
+      assertEquals(info.title(), book.getTitle());
+      assertEquals(info.author(), book.getAuthor());
+      assertEquals(info.publisher(), book.getPublisher());
+      assertEquals(info.publicationDate(), book.getPublicationDate());
+      assertEquals(info.price(), book.getPrice());
+      assertEquals(info.quantity(), book.getQuantity());
+      assertEquals(info.categories(), book.getCategories());
+      assertEquals(info.description(), book.getDescription());
+      assertEquals(info.language(), book.getLanguage());
+    }
+  }
+
+  @Nested
+  @DisplayName("toDTO() method tests")
+  class ToDTOTests {
+
+    @Test
+    @DisplayName("Should convert Book entity to BookDTO preserving all fields")
+    void testToDTO() {
+      Book book = Book.builder()
+          .isbn(123L)
+          .title("T")
+          .author("A")
+          .publisher("P")
+          .publicationDate(LocalDate.of(2020, 1, 1))
+          .price(9.99)
+          .quantity(5)
+          .categories(List.of(Category.FICTION))
+          .description("d")
+          .language("FR")
+          .build();
+
+      BookDTO dto = BookConverter.toDTO(book);
+
+      assertEquals(123L, dto.getIsbn());
+      assertEquals("T", dto.getTitle());
+      assertEquals("A", dto.getAuthor());
+      assertEquals("P", dto.getPublisher());
+      assertEquals(LocalDate.of(2020, 1, 1), dto.getPublicationDate());
+      assertEquals(9.99, dto.getPrice());
+      assertEquals(5, dto.getQuantity());
+      assertEquals(List.of(Category.FICTION), dto.getCategories());
+      assertEquals("d", dto.getDescription());
+      assertEquals("FR", dto.getLanguage());
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/entity/BookTest.java

@@ -0,0 +1,75 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.entity;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.IllegalBookQuantityException;
+import java.time.LocalDate;
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookTest {
+
+  @Test
+  @DisplayName("Builder should create a valid Book instance")
+  void testBookBuilder() {
+    long isbn = 9780321125217L;
+    Book book = Book.builder()
+        .isbn(isbn)
+        .title("Domain-Driven Design")
+        .author("Eric Evans")
+        .publisher("Addison-Wesley")
+        .publicationDate(LocalDate.of(2003, 8, 22))
+        .price(54.99)
+        .quantity(10)
+        .categories(List.of(Category.SCIENCE, Category.REFERENCE))
+        .description("Tackling complexity in the heart of software")
+        .language("EN")
+        .build();
+
+    assertEquals(isbn, book.getIsbn());
+    assertEquals("Domain-Driven Design", book.getTitle());
+    assertEquals("Eric Evans", book.getAuthor());
+    assertEquals("Addison-Wesley", book.getPublisher());
+    assertEquals(LocalDate.of(2003, 8, 22), book.getPublicationDate());
+    assertEquals(54.99, book.getPrice());
+    assertEquals(10, book.getQuantity());
+    assertEquals(List.of(Category.SCIENCE, Category.REFERENCE), book.getCategories());
+    assertEquals("EN", book.getLanguage());
+  }
+
+  @Nested
+  @DisplayName("Stock management")
+  class StockTests {
+
+    @Test
+    @DisplayName("addStock should increase the quantity")
+    void testAddStock() {
+      Book book = Book.builder().quantity(5).build();
+      book.addStock(7);
+      assertEquals(12, book.getQuantity());
+    }
+
+    @Test
+    @DisplayName("removeStock should decrease the quantity")
+    void testRemoveStock() throws IllegalBookQuantityException {
+      Book book = Book.builder().quantity(5).build();
+      book.removeStock(3);
+      assertEquals(2, book.getQuantity());
+    }
+
+    @Test
+    @DisplayName("removeStock should throw when removing more than available")
+    void testRemoveTooMuchStock() {
+      Book book = Book.builder().quantity(5).build();
+      IllegalBookQuantityException exception = assertThrows(
+          IllegalBookQuantityException.class,
+          () -> book.removeStock(10)
+      );
+      assertEquals(5, book.getQuantity());
+      assertTrue(exception.getMessage().contains("10"));
+      assertTrue(exception.getMessage().contains("5"));
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/BookAlreadyExistsExceptionTest.java

@@ -0,0 +1,26 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookAlreadyExistsExceptionTest {
+
+  @Test
+  @DisplayName("Exception message should contain the ISBN provided")
+  void testExceptionMessageContainsIsbn() {
+    long isbn = 9780321125217L;
+
+    BookAlreadyExistsException exception = new BookAlreadyExistsException(isbn);
+
+    assertTrue(exception.getMessage().contains(String.valueOf(isbn)));
+  }
+
+  @Test
+  @DisplayName("Exception should expose its message constant")
+  void testConstantMessage() {
+    assertEquals("A book with isbn {0} already exists",
+        BookAlreadyExistsException.A_BOOK_WITH_ISBN_ALREADY_EXISTS_MESSAGE);
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/BookNotFoundExceptionTest.java

@@ -0,0 +1,37 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookNotFoundExceptionTest {
+
+  @Test
+  @DisplayName("Exception message should contain the ISBN provided")
+  void testExceptionMessageContainsIsbn() {
+    long isbn = 9780321125217L;
+
+    BookNotFoundException exception = new BookNotFoundException(isbn);
+
+    assertTrue(exception.getMessage().contains(String.valueOf(isbn)));
+  }
+
+  @Test
+  @DisplayName("Exception should expose its message constant")
+  void testConstantMessage() {
+    assertEquals("The book with isbn {0} does not exist",
+        BookNotFoundException.THE_BOOK_WITH_ISBN_DOES_NOT_EXIST_MESSAGE);
+  }
+
+  @Test
+  @DisplayName("Exception should be properly thrown and caught")
+  void testExceptionCanBeThrownAndCaught() {
+    long isbn = 1L;
+    try {
+      throw new BookNotFoundException(isbn);
+    } catch (BookNotFoundException e) {
+      assertTrue(e.getMessage().contains("1"));
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/IllegalBookQuantityExceptionTest.java

@@ -0,0 +1,33 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import java.text.MessageFormat;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class IllegalBookQuantityExceptionTest {
+
+  @Test
+  @DisplayName("Exception message should contain the requested and actual quantities")
+  void testExceptionMessageContainsQuantities() {
+    IllegalBookQuantityException exception = new IllegalBookQuantityException(10, 3);
+    String expected = "Cannot remove 10 units from 3 units in stock";
+    assertEquals(expected, exception.getMessage());
+  }
+
+  @ParameterizedTest
+  @CsvSource({
+      "10, 3",
+      "100, 0",
+      "5, 4"
+  })
+  @DisplayName("Message should be formatted using the constant template")
+  void testFormattedMessage(int needed, int actual) {
+    IllegalBookQuantityException exception = new IllegalBookQuantityException(needed, actual);
+    String expected = MessageFormat.format(IllegalBookQuantityException.CANNOT_REMOVE_STOCK, needed, actual);
+    assertEquals(expected, exception.getMessage());
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/exception/NotValidBookExceptionTest.java

@@ -0,0 +1,44 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.exception;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class NotValidBookExceptionTest {
+
+  @Test
+  @DisplayName("Exception should be created with the provided message")
+  void testExceptionCreation() {
+    String msg = "title cannot be blank";
+    NotValidBookException exception = new NotValidBookException(msg);
+    assertEquals(msg, exception.getMessage());
+  }
+
+  @ParameterizedTest
+  @ValueSource(strings = {
+      "Title cannot be blank",
+      "Author cannot be blank",
+      "Price must be strictly positive",
+      "At least one category is required"
+  })
+  @DisplayName("Exception should propagate any validation message")
+  void testExceptionWithDifferentMessages(String message) {
+    NotValidBookException exception = new NotValidBookException(message);
+    assertEquals(message, exception.getMessage());
+  }
+
+  @Test
+  @DisplayName("Exception should be catchable as a general Exception")
+  void testExceptionInheritance() {
+    String msg = "invalid book";
+    try {
+      throw new NotValidBookException(msg);
+    } catch (Exception e) {
+      assertEquals(NotValidBookException.class, e.getClass());
+      assertEquals(msg, e.getMessage());
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/repository/BookRepositoryTest.java

@@ -0,0 +1,149 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.repository;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Book;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Category;
+import java.time.LocalDate;
+import java.util.List;
+import java.util.Optional;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookRepositoryTest {
+
+  private BookRepository repository;
+  private Book book1;
+  private Book book2;
+
+  @BeforeEach
+  void setUp() {
+    repository = new BookRepository();
+
+    book1 = Book.builder()
+        .isbn(1111111111111L)
+        .title("Book One")
+        .author("Author A")
+        .publisher("Pub")
+        .publicationDate(LocalDate.of(2020, 1, 1))
+        .price(10.0)
+        .quantity(2)
+        .categories(List.of(Category.FICTION))
+        .language("EN")
+        .build();
+
+    book2 = Book.builder()
+        .isbn(2222222222222L)
+        .title("Book Two")
+        .author("Author B")
+        .publisher("Pub")
+        .publicationDate(LocalDate.of(2021, 1, 1))
+        .price(20.0)
+        .quantity(0)
+        .categories(List.of(Category.HISTORY))
+        .language("FR")
+        .build();
+  }
+
+  @Test
+  @DisplayName("New repository should be empty")
+  void testNewRepositoryIsEmpty() {
+    assertTrue(repository.findAll().isEmpty());
+  }
+
+  @Nested
+  @DisplayName("Save operations")
+  class SaveOperations {
+
+    @Test
+    @DisplayName("Save should add a new book")
+    void testSave() {
+      Book saved = repository.save(book1);
+      assertEquals(1, repository.findAll().size());
+      assertEquals(book1.getIsbn(), saved.getIsbn());
+    }
+
+    @Test
+    @DisplayName("Save should replace existing book with same ISBN (idempotency)")
+    void testSaveReplacesExisting() {
+      repository.save(book1);
+      Book updated = Book.builder()
+          .isbn(book1.getIsbn())
+          .title("New title")
+          .author("Author A")
+          .publisher("Pub")
+          .publicationDate(LocalDate.of(2020, 1, 1))
+          .price(10.0)
+          .quantity(99)
+          .categories(List.of(Category.FICTION))
+          .language("EN")
+          .build();
+
+      repository.save(updated);
+
+      assertEquals(1, repository.findAll().size());
+      assertEquals(99, repository.findByIsbn(book1.getIsbn()).orElseThrow().getQuantity());
+      assertEquals("New title", repository.findByIsbn(book1.getIsbn()).orElseThrow().getTitle());
+    }
+  }
+
+  @Nested
+  @DisplayName("Find operations")
+  class FindOperations {
+
+    @BeforeEach
+    void seed() {
+      repository.save(book1);
+      repository.save(book2);
+    }
+
+    @Test
+    @DisplayName("findByIsbn returns the matching book")
+    void testFindByIsbn() {
+      Optional<Book> found = repository.findByIsbn(book1.getIsbn());
+      assertTrue(found.isPresent());
+      assertEquals(book1.getTitle(), found.get().getTitle());
+    }
+
+    @Test
+    @DisplayName("findByIsbn returns empty when not found")
+    void testFindByIsbnNotFound() {
+      assertTrue(repository.findByIsbn(99L).isEmpty());
+    }
+
+    @Test
+    @DisplayName("existsByIsbn returns true / false consistently")
+    void testExistsByIsbn() {
+      assertTrue(repository.existsByIsbn(book1.getIsbn()));
+      assertFalse(repository.existsByIsbn(99L));
+    }
+  }
+
+  @Nested
+  @DisplayName("Delete operations")
+  class DeleteOperations {
+
+    @BeforeEach
+    void seed() {
+      repository.save(book1);
+      repository.save(book2);
+    }
+
+    @Test
+    @DisplayName("delete should remove the specified book")
+    void testDelete() {
+      repository.delete(book1);
+      assertEquals(1, repository.findAll().size());
+      assertFalse(repository.existsByIsbn(book1.getIsbn()));
+    }
+
+    @Test
+    @DisplayName("deleteAll should clear the repository")
+    void testDeleteAll() {
+      repository.deleteAll();
+      assertTrue(repository.findAll().isEmpty());
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/usecase/BookUseCaseTest.java

@@ -0,0 +1,152 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.usecase;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookDTO;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Book;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Category;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.BookAlreadyExistsException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.BookNotFoundException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.NotValidBookException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.repository.BookRepository;
+import java.time.LocalDate;
+import java.util.List;
+import java.util.Optional;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class BookUseCaseTest {
+
+  @Mock
+  private BookRepository bookRepository;
+
+  @InjectMocks
+  private BookUseCase bookUseCase;
+
+  private BookInfo validInfo;
+  private Book validBook;
+
+  @BeforeEach
+  void setUp() {
+    validInfo = new BookInfo(
+        9780321125217L,
+        "DDD",
+        "Evans",
+        "Addison-Wesley",
+        LocalDate.of(2003, 8, 22),
+        54.99,
+        10,
+        List.of(Category.SCIENCE),
+        "desc",
+        "EN"
+    );
+    validBook = Book.builder()
+        .isbn(validInfo.isbn())
+        .title(validInfo.title())
+        .author(validInfo.author())
+        .publisher(validInfo.publisher())
+        .publicationDate(validInfo.publicationDate())
+        .price(validInfo.price())
+        .quantity(validInfo.quantity())
+        .categories(validInfo.categories())
+        .description(validInfo.description())
+        .language(validInfo.language())
+        .build();
+  }
+
+  @Nested
+  @DisplayName("registerBook tests")
+  class RegisterTests {
+
+    @Test
+    @DisplayName("Should register a new book and return its ISBN")
+    void testRegisterBook() throws NotValidBookException, BookAlreadyExistsException {
+      when(bookRepository.existsByIsbn(validInfo.isbn())).thenReturn(false);
+      when(bookRepository.save(any(Book.class))).thenReturn(validBook);
+
+      long isbn = bookUseCase.registerBook(validInfo);
+
+      assertEquals(validInfo.isbn(), isbn);
+      verify(bookRepository).existsByIsbn(validInfo.isbn());
+      verify(bookRepository).save(any(Book.class));
+    }
+
+    @Test
+    @DisplayName("Should reject invalid book information without touching the repository")
+    void testRegisterInvalidBook() {
+      BookInfo invalid = new BookInfo(0L, "", "", "", null, -1, -1, null, "", "");
+      assertThrows(NotValidBookException.class, () -> bookUseCase.registerBook(invalid));
+      verifyNoInteractions(bookRepository);
+    }
+
+    @Test
+    @DisplayName("Should reject duplicate ISBN")
+    void testRegisterDuplicate() {
+      when(bookRepository.existsByIsbn(validInfo.isbn())).thenReturn(true);
+      assertThrows(BookAlreadyExistsException.class, () -> bookUseCase.registerBook(validInfo));
+      verify(bookRepository).existsByIsbn(validInfo.isbn());
+      verify(bookRepository, never()).save(any(Book.class));
+    }
+  }
+
+  @Nested
+  @DisplayName("getBookByIsbn tests")
+  class GetByIdTests {
+
+    @Test
+    @DisplayName("Should return the BookDTO when ISBN exists")
+    void testGetById() throws BookNotFoundException {
+      when(bookRepository.findByIsbn(validInfo.isbn())).thenReturn(Optional.of(validBook));
+
+      BookDTO dto = bookUseCase.getBookByIsbn(validInfo.isbn());
+
+      assertEquals(validInfo.isbn(), dto.getIsbn());
+      assertEquals(validInfo.title(), dto.getTitle());
+    }
+
+    @Test
+    @DisplayName("Should throw when ISBN does not exist")
+    void testGetByIdNotFound() {
+      when(bookRepository.findByIsbn(99L)).thenReturn(Optional.empty());
+      assertThrows(BookNotFoundException.class, () -> bookUseCase.getBookByIsbn(99L));
+    }
+  }
+
+  @Nested
+  @DisplayName("getAllBooks tests")
+  class GetAllBooksTests {
+
+    @Test
+    @DisplayName("Should map every book returned by the repository to a DTO")
+    void testGetAllBooks() {
+      when(bookRepository.findAll()).thenReturn(List.of(validBook));
+
+      List<BookDTO> result = bookUseCase.getAllBooks();
+
+      assertEquals(1, result.size());
+      assertEquals(validBook.getIsbn(), result.getFirst().getIsbn());
+      assertEquals(validBook.getTitle(), result.getFirst().getTitle());
+      verify(bookRepository).findAll();
+    }
+
+    @Test
+    @DisplayName("Should return an empty list when no book is stored")
+    void testGetAllBooksWhenEmpty() {
+      when(bookRepository.findAll()).thenReturn(List.of());
+
+      List<BookDTO> result = bookUseCase.getAllBooks();
+
+      assertTrue(result.isEmpty());
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/book/validator/BookValidatorTest.java

@@ -0,0 +1,167 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.book.validator;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Category;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.NotValidBookException;
+import java.time.LocalDate;
+import java.util.List;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class BookValidatorTest {
+
+  private BookInfo valid() {
+    return new BookInfo(
+        9780321125217L,
+        "Domain-Driven Design",
+        "Eric Evans",
+        "Addison-Wesley",
+        LocalDate.of(2003, 8, 22),
+        54.99,
+        10,
+        List.of(Category.SCIENCE),
+        "Tackling complexity in the heart of software",
+        "EN"
+    );
+  }
+
+  @Test
+  @DisplayName("Should accept a valid BookInfo")
+  void testValidBook() {
+    assertDoesNotThrow(() -> BookValidator.validate(valid()));
+  }
+
+  @Nested
+  @DisplayName("ISBN validation")
+  class IsbnTests {
+
+    @ParameterizedTest
+    @ValueSource(longs = {0L, -1L, -9999L})
+    @DisplayName("Should reject ISBN that is not strictly positive")
+    void testInvalidIsbn(long isbn) {
+      BookInfo info = new BookInfo(isbn, "T", "A", "P", LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.ISBN_MUST_BE_POSITIVE, ex.getMessage());
+    }
+  }
+
+  @Nested
+  @DisplayName("Title validation")
+  class TitleTests {
+
+    @ParameterizedTest
+    @ValueSource(strings = {"", " ", "\t", "\n"})
+    @DisplayName("Should reject blank title")
+    void testBlankTitle(String title) {
+      BookInfo info = new BookInfo(1L, title, "A", "P", LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.TITLE_CANNOT_BE_BLANK, ex.getMessage());
+    }
+
+    @Test
+    @DisplayName("Should reject null title")
+    void testNullTitle() {
+      BookInfo info = new BookInfo(1L, null, "A", "P", LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.TITLE_CANNOT_BE_BLANK, ex.getMessage());
+    }
+
+    @Test
+    @DisplayName("Should reject title longer than 255 characters")
+    void testTitleTooLong() {
+      String longTitle = "a".repeat(256);
+      BookInfo info = new BookInfo(1L, longTitle, "A", "P", LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.TITLE_TOO_LONG, ex.getMessage());
+    }
+  }
+
+  @Nested
+  @DisplayName("Author / Publisher validation")
+  class AuthorPublisherTests {
+
+    @ParameterizedTest
+    @ValueSource(strings = {"", " ", "\t"})
+    @DisplayName("Should reject blank author")
+    void testBlankAuthor(String author) {
+      BookInfo info = new BookInfo(1L, "T", author, "P", LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.AUTHOR_CANNOT_BE_BLANK, ex.getMessage());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"", " ", "\t"})
+    @DisplayName("Should reject blank publisher")
+    void testBlankPublisher(String publisher) {
+      BookInfo info = new BookInfo(1L, "T", "A", publisher, LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.PUBLISHER_CANNOT_BE_BLANK, ex.getMessage());
+    }
+  }
+
+  @Nested
+  @DisplayName("Date / Price / Quantity validation")
+  class NumericTests {
+
+    @Test
+    @DisplayName("Should reject null publication date")
+    void testNullDate() {
+      BookInfo info = new BookInfo(1L, "T", "A", "P", null, 1.0, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.PUBLICATION_DATE_REQUIRED, ex.getMessage());
+    }
+
+    @ParameterizedTest
+    @ValueSource(doubles = {0.0, -0.01, -10.0})
+    @DisplayName("Should reject non-positive price")
+    void testNonPositivePrice(double price) {
+      BookInfo info = new BookInfo(1L, "T", "A", "P", LocalDate.now(), price, 0, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.PRICE_MUST_BE_POSITIVE, ex.getMessage());
+    }
+
+    @ParameterizedTest
+    @ValueSource(ints = {-1, -100})
+    @DisplayName("Should reject negative quantity")
+    void testNegativeQuantity(int quantity) {
+      BookInfo info = new BookInfo(1L, "T", "A", "P", LocalDate.now(), 1.0, quantity, List.of(Category.SCIENCE), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.QUANTITY_MUST_BE_POSITIVE_OR_ZERO, ex.getMessage());
+    }
+  }
+
+  @Nested
+  @DisplayName("Categories / Language validation")
+  class MetadataTests {
+
+    @Test
+    @DisplayName("Should reject empty categories")
+    void testEmptyCategories() {
+      BookInfo info = new BookInfo(1L, "T", "A", "P", LocalDate.now(), 1.0, 0, List.of(), "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.CATEGORIES_REQUIRED, ex.getMessage());
+    }
+
+    @Test
+    @DisplayName("Should reject null categories")
+    void testNullCategories() {
+      BookInfo info = new BookInfo(1L, "T", "A", "P", LocalDate.now(), 1.0, 0, null, "", "EN");
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.CATEGORIES_REQUIRED, ex.getMessage());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"", " ", "\t"})
+    @DisplayName("Should reject blank language")
+    void testBlankLanguage(String language) {
+      BookInfo info = new BookInfo(1L, "T", "A", "P", LocalDate.now(), 1.0, 0, List.of(Category.SCIENCE), "", language);
+      NotValidBookException ex = assertThrows(NotValidBookException.class, () -> BookValidator.validate(info));
+      assertEquals(BookValidator.LANGUAGE_CANNOT_BE_BLANK, ex.getMessage());
+    }
+  }
+}

mylibrary/src/test/java/fr/iut_fbleau/but3/dev62/mylibrary/features/book/BookSteps.java

@@ -0,0 +1,106 @@
+package fr.iut_fbleau.but3.dev62.mylibrary.features.book;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookDTO;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.BookInfo;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.entity.Category;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.BookAlreadyExistsException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.BookNotFoundException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.exception.NotValidBookException;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.repository.BookRepository;
+import fr.iut_fbleau.but3.dev62.mylibrary.book.usecase.BookUseCase;
+import io.cucumber.datatable.DataTable;
+import io.cucumber.java.en.And;
+import io.cucumber.java.en.Given;
+import io.cucumber.java.en.Then;
+import io.cucumber.java.en.When;
+import java.time.LocalDate;
+import java.util.List;
+import java.util.Map;
+
+public class BookSteps {
+
+  private final BookRepository bookRepository = new BookRepository();
+  private final BookUseCase bookUseCase = new BookUseCase(bookRepository);
+
+  private long lastRegisteredIsbn;
+  private BookDTO retrievedBook;
+  private List<BookDTO> allBooks;
+  private Exception lastException;
+
+  @Given("the catalog has the following books:")
+  public void theCatalogHasTheFollowingBooks(DataTable dataTable) throws NotValidBookException, BookAlreadyExistsException {
+    bookRepository.deleteAll();
+    for (Map<String, String> row : dataTable.asMaps(String.class, String.class)) {
+      bookUseCase.registerBook(toBookInfo(row));
+    }
+  }
+
+  @When("I register a new book with the following information:")
+  public void iRegisterANewBook(DataTable dataTable) throws NotValidBookException, BookAlreadyExistsException {
+    Map<String, String> row = dataTable.asMaps(String.class, String.class).getFirst();
+    lastRegisteredIsbn = bookUseCase.registerBook(toBookInfo(row));
+  }
+
+  @When("I try to register a new book with the following information:")
+  public void iTryToRegisterANewBook(DataTable dataTable) {
+    Map<String, String> row = dataTable.asMaps(String.class, String.class).getFirst();
+    lastException = assertThrows(Exception.class, () -> bookUseCase.registerBook(toBookInfo(row)));
+  }
+
+  @When("I request the book with isbn {long}")
+  public void iRequestTheBook(long isbn) throws BookNotFoundException {
+    retrievedBook = bookUseCase.getBookByIsbn(isbn);
+  }
+
+  @When("I list all books")
+  public void iListAllBooks() {
+    allBooks = bookUseCase.getAllBooks();
+  }
+
+  @Then("the book is created")
+  public void theBookIsCreated() {
+    assertNotNull(lastRegisteredIsbn);
+  }
+
+  @And("the catalog now has {int} book(s)")
+  public void theCatalogNowHasNBooks(int expected) {
+    assertEquals(expected, bookRepository.findAll().size());
+  }
+
+  @Then("the registration fails with a {string}")
+  public void theRegistrationFailsWith(String exceptionSimpleName) {
+    assertNotNull(lastException);
+    assertEquals(exceptionSimpleName, lastException.getClass().getSimpleName());
+  }
+
+  @Then("I receive a book whose title is {string}")
+  public void iReceiveABookWhoseTitleIs(String title) {
+    assertNotNull(retrievedBook);
+    assertEquals(title, retrievedBook.getTitle());
+  }
+
+  @Then("I receive {int} book(s)")
+  public void iReceiveNBooks(int expected) {
+    assertNotNull(allBooks);
+    assertEquals(expected, allBooks.size());
+  }
+
+  private static BookInfo toBookInfo(Map<String, String> row) {
+    return new BookInfo(
+        Long.parseLong(row.get("isbn")),
+        row.get("titre"),
+        row.get("auteur"),
+        row.get("editeur"),
+        LocalDate.parse(row.get("datePublication")),
+        Double.parseDouble(row.get("prix")),
+        Integer.parseInt(row.get("stock")),
+        List.of(Category.valueOf(row.get("categorie"))),
+        "",
+        row.get("langue")
+    );
+  }
+}

mylibrary/src/test/resources/features/book.feature

@@ -0,0 +1,40 @@
+# language: en
+
+Feature: Manage book catalog
+
+  Scenario: Register a new book in the catalog
+    When I register a new book with the following information:
+      | isbn          | titre    | auteur  | editeur | datePublication | prix  | stock | categorie | langue |
+      | 9780321125217 | DDD      | Evans   | AW      | 2003-08-22      | 54.99 | 10    | SCIENCE   | EN     |
+    Then the book is created
+    And the catalog now has 1 book
+
+  Scenario: Reject duplicate ISBN
+    Given the catalog has the following books:
+      | isbn          | titre    | auteur  | editeur | datePublication | prix  | stock | categorie | langue |
+      | 9780321125217 | DDD      | Evans   | AW      | 2003-08-22      | 54.99 | 10    | SCIENCE   | EN     |
+    When I try to register a new book with the following information:
+      | isbn          | titre    | auteur  | editeur | datePublication | prix  | stock | categorie | langue |
+      | 9780321125217 | DDD copy | Evans   | AW      | 2003-08-22      | 54.99 | 10    | SCIENCE   | EN     |
+    Then the registration fails with a "BookAlreadyExistsException"
+
+  Scenario: Reject invalid book information
+    When I try to register a new book with the following information:
+      | isbn          | titre | auteur | editeur | datePublication | prix | stock | categorie | langue |
+      | 9780321125217 |       | Evans  | AW      | 2003-08-22      | 0    | -1    | SCIENCE   | EN     |
+    Then the registration fails with a "NotValidBookException"
+
+  Scenario: Retrieve a book by its ISBN
+    Given the catalog has the following books:
+      | isbn          | titre    | auteur  | editeur | datePublication | prix  | stock | categorie | langue |
+      | 9780321125217 | DDD      | Evans   | AW      | 2003-08-22      | 54.99 | 10    | SCIENCE   | EN     |
+    When I request the book with isbn 9780321125217
+    Then I receive a book whose title is "DDD"
+
+  Scenario: List all books in the catalog
+    Given the catalog has the following books:
+      | isbn          | titre    | auteur  | editeur | datePublication | prix  | stock | categorie | langue |
+      | 9780321125217 | DDD      | Evans   | AW      | 2003-08-22      | 54.99 | 10    | SCIENCE   | EN     |
+      | 9780132350884 | Clean    | Martin  | PH      | 2008-08-01      | 30.00 | 5     | SCIENCE   | EN     |
+    When I list all books
+    Then I receive 2 books