diff --git a/.gitea/workflows/lint.yml b/.gitea/workflows/lint.yml
index 6cbfc6d..5194ae0 100644
--- a/.gitea/workflows/lint.yml
+++ b/.gitea/workflows/lint.yml
@@ -24,3 +24,6 @@ jobs:
 
       - name: Check linting
         run: deno lint
+
+      - name: Run tests
+        run: deno test -A --no-check tests/
diff --git a/deno.json b/deno.json
index c7f729b..1c0cfb3 100644
--- a/deno.json
+++ b/deno.json
@@ -9,7 +9,8 @@
     "start": "deno run -A --unstable-ffi --watch=static/,routes/ dev.ts",
     "build": "deno run -A --unstable-ffi dev.ts build",
     "preview": "deno run -A --unstable-ffi main.ts",
-    "update": "deno run -A -r https://fresh.deno.dev/update ."
+    "update": "deno run -A -r https://fresh.deno.dev/update .",
+    "test": "deno test -A --no-check tests/"
   },
   "lint": {
     "rules": {
@@ -35,6 +36,9 @@
     "@preact/signals": "https://esm.sh/*@preact/signals@1.2.2",
     "@preact/signals-core": "https://esm.sh/*@preact/signals-core@1.5.1",
     "$std/": "https://deno.land/std@0.216.0/",
+    "@std/assert": "jsr:@std/assert@^1.0.0",
+    "@std/testing": "jsr:@std/testing@^1.0.0",
+    "happy-dom": "npm:happy-dom@^16.0.0",
     "$root/": "./",
     "$apps/": "./routes/(apps)/"
   },
diff --git a/tests/e2e/.gitkeep b/tests/e2e/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/tests/helpers/api_mock.ts b/tests/helpers/api_mock.ts
new file mode 100644
index 0000000..0f8af47
--- /dev/null
+++ b/tests/helpers/api_mock.ts
@@ -0,0 +1,123 @@
+// Mock de fetch() pour les tests — supporte méthodes HTTP et status codes
+
+type HttpMethod = "GET" | "POST" | "PUT" | "DELETE";
+
+export interface MockRoute {
+  method?: HttpMethod;
+  status?: number;
+  body?: unknown;
+  headers?: Record<string, string>;
+}
+
+// deno-lint-ignore no-explicit-any
+let _originalFetch: ((input: any, init?: any) => Promise<Response>) | null =
+  null;
+let _calls: { url: string; method: string; body?: unknown }[] = [];
+
+/**
+ * Remplace globalThis.fetch par un mock configurable.
+ *
+ * Usage simple (GET 200 par défaut) :
+ *   mockFetch({ "/students": studentsData })
+ *
+ * Usage avancé (méthode + status) :
+ *   mockFetch({ "/students": { method: "POST", status: 201, body: newStudent } })
+ */
+export function mockFetch(
+  routes: Record<string, unknown | MockRoute>,
+): void {
+  _originalFetch = globalThis.fetch;
+  _calls = [];
+
+  globalThis.fetch = (
+    input: string | URL | Request,
+    init?: RequestInit,
+  ): Promise<Response> => {
+    const url = typeof input === "string"
+      ? input
+      : input instanceof URL
+      ? input.toString()
+      : input.url;
+    const method = (init?.method ?? "GET").toUpperCase();
+
+    // Parse le body si présent
+    let reqBody: unknown = undefined;
+    if (init?.body) {
+      try {
+        reqBody = JSON.parse(init.body as string);
+      } catch {
+        reqBody = init.body;
+      }
+    }
+
+    _calls.push({ url, method, body: reqBody });
+
+    for (const [pattern, config] of Object.entries(routes)) {
+      if (!url.includes(pattern)) continue;
+
+      // Config simple : la valeur est directement le body de réponse (GET 200)
+      if (!isRouteConfig(config)) {
+        return new Response(JSON.stringify(config), {
+          status: 200,
+          headers: { "Content-Type": "application/json" },
+        });
+      }
+
+      // Config avancée : vérifier la méthode si spécifiée
+      if (config.method && config.method !== method) continue;
+
+      const status = config.status ?? 200;
+
+      // 204 : pas de body
+      if (status === 204) {
+        return new Response(null, { status: 204 });
+      }
+
+      return new Response(
+        config.body !== undefined ? JSON.stringify(config.body) : null,
+        {
+          status,
+          headers: {
+            "Content-Type": "application/json",
+            ...config.headers,
+          },
+        },
+      );
+    }
+
+    return new Response(JSON.stringify({ error: "Not Found" }), {
+      status: 404,
+      headers: { "Content-Type": "application/json" },
+    });
+  };
+}
+
+/**
+ * Restaure le fetch original.
+ */
+export function restoreFetch(): void {
+  if (_originalFetch) {
+    globalThis.fetch = _originalFetch;
+    _originalFetch = null;
+  }
+  _calls = [];
+}
+
+/**
+ * Retourne la liste des appels fetch interceptés.
+ */
+export function getFetchCalls(): {
+  url: string;
+  method: string;
+  body?: unknown;
+}[] {
+  return [..._calls];
+}
+
+function isRouteConfig(value: unknown): value is MockRoute {
+  if (typeof value !== "object" || value === null || Array.isArray(value)) {
+    return false;
+  }
+  const v = value as Record<string, unknown>;
+  return "status" in v || "method" in v || "body" in v;
+}
diff --git a/tests/helpers/db_mock.ts b/tests/helpers/db_mock.ts
new file mode 100644
index 0000000..4d18bb9
--- /dev/null
+++ b/tests/helpers/db_mock.ts
@@ -0,0 +1,122 @@
+// Mock de la couche Drizzle pour les tests unitaires/intégration
+// Permet de tester les handlers sans connexion PostgreSQL
+
+export interface MockQueryResult<T> {
+  rows: T[];
+}
+
+export interface MockDbConfig {
+  // Table name → array of rows
+  // deno-lint-ignore no-explicit-any
+  tables: Record<string, Record<string, any>[]>;
+}
+
+/**
+ * Crée un mock de la DB Drizzle.
+ * Simule select/insert/update/delete avec un store en mémoire.
+ *
+ * Usage :
+ * ```ts
+ * const db = createMockDb({
+ *   tables: {
+ *     students: [{ numEtud: 21212006, nom: "Dupont", ... }],
+ *     notes: [],
+ *   }
+ * });
+ *
+ * // Lire toutes les lignes d'une table
+ * const rows = db.getTable("students");
+ *
+ * // Insérer
+ * db.insert("students", { numEtud: 21212009, nom: "Test", ... });
+ *
+ * // Trouver par clé
+ * const student = db.findOne("students", (r) => r.numEtud === 21212006);
+ *
+ * // Supprimer
+ * db.deleteWhere("students", (r) => r.numEtud === 21212006);
+ * ```
+ */
+export function createMockDb(config: MockDbConfig) {
+  // Deep clone pour éviter les mutations entre tests
+  // deno-lint-ignore no-explicit-any
+  const tables: Record<string, Record<string, any>[]> = {};
+  for (const [name, rows] of Object.entries(config.tables)) {
+    tables[name] = rows.map((r) => ({ ...r }));
+  }
+
+  return {
+    /** Retourne toutes les lignes d'une table */
+    getTable<T = Record<string, unknown>>(name: string): T[] {
+      return (tables[name] ?? []) as T[];
+    },
+
+    /** Retourne les lignes qui matchent le filtre */
+    findMany<T = Record<string, unknown>>(
+      name: string,
+      predicate: (row: T) => boolean,
+    ): T[] {
+      return (this.getTable<T>(name)).filter(predicate);
+    },
+
+    /** Retourne la première ligne qui matche, ou undefined */
+    findOne<T = Record<string, unknown>>(
+      name: string,
+      predicate: (row: T) => boolean,
+    ): T | undefined {
+      return (this.getTable<T>(name)).find(predicate);
+    },
+
+    /** Insère une ligne dans la table */
+    insert<T = Record<string, unknown>>(name: string, row: T): T {
+      if (!tables[name]) tables[name] = [];
+      const copy = { ...row } as T;
+      // deno-lint-ignore no-explicit-any
+      tables[name].push(copy as any);
+      return copy;
+    },
+
+    /** Met à jour les lignes qui matchent le prédicat */
+    updateWhere<T = Record<string, unknown>>(
+      name: string,
+      predicate: (row: T) => boolean,
+      updates: Partial<T>,
+    ): number {
+      const rows = this.getTable<T>(name);
+      let count = 0;
+      for (const row of rows) {
+        if (predicate(row)) {
+          Object.assign(row as Record<string, unknown>, updates);
+          count++;
+        }
+      }
+      return count;
+    },
+
+    /** Supprime les lignes qui matchent le prédicat */
+    deleteWhere<T = Record<string, unknown>>(
+      name: string,
+      predicate: (row: T) => boolean,
+    ): number {
+      const before = (tables[name] ?? []).length;
+      tables[name] = (tables[name] ?? []).filter(
+        (r) => !predicate(r as unknown as T),
+      );
+      return before - tables[name].length;
+    },
+
+    /** Vide une table */
+    clear(name: string): void {
+      tables[name] = [];
+    },
+
+    /** Vide toutes les tables */
+    reset(): void {
+      for (const name of Object.keys(tables)) {
+        tables[name] = [];
+      }
+    },
+  };
+}
+
+export type MockDb = ReturnType<typeof createMockDb>;
diff --git a/tests/helpers/fixtures.ts b/tests/helpers/fixtures.ts
new file mode 100644
index 0000000..67ece22
--- /dev/null
+++ b/tests/helpers/fixtures.ts
@@ -0,0 +1,137 @@
+// Types et données de test alignés sur l'API REST PolyMPR
+
+// --- Types ---
+
+export interface Student {
+  numEtud: number;
+  nom: string;
+  prenom: string;
+  idPromo: string;
+}
+
+export interface Promotion {
+  idPromo: string;
+  annee: string;
+}
+
+export interface Prof {
+  id: number;
+  nom: string;
+  prenom: string;
+}
+
+export interface Module {
+  id: string;
+  nom: string;
+}
+
+export interface Note {
+  note: number;
+  numEtud: number;
+  idModule: string;
+}
+
+export interface UE {
+  id: number;
+  nom: string;
+}
+
+export interface UeModule {
+  idModule: string;
+  idUE: number;
+  idPromo: string;
+  coeff: number;
+}
+
+export interface Enseignement {
+  idProf: number;
+  idModule: string;
+  idPromo: string;
+}
+
+export interface Ajustement {
+  numEtud: number;
+  idUE: number;
+  valeur: number;
+}
+
+export interface ImportResult {
+  imported: number;
+  errors: { line: number; message: string }[];
+}
+
+export interface ApiError {
+  error: string;
+}
+
+// --- Fixtures ---
+
+export const students: Student[] = [
+  { numEtud: 21212006, nom: "Dupont", prenom: "Jean", idPromo: "4AFISE25/26" },
+  {
+    numEtud: 21212007,
+    nom: "Martin",
+    prenom: "Alice",
+    idPromo: "4AFISE25/26",
+  },
+  {
+    numEtud: 21212008,
+    nom: "Durand",
+    prenom: "Claire",
+    idPromo: "3AFISE25/26",
+  },
+];
+
+export const promotions: Promotion[] = [
+  { idPromo: "4AFISE25/26", annee: "2025" },
+  { idPromo: "3AFISE25/26", annee: "2025" },
+  { idPromo: "JIA4A2526", annee: "2025" },
+];
+
+export const profs: Prof[] = [
+  { id: 1, nom: "Leclerc", prenom: "Jean" },
+  { id: 2, nom: "Moreau", prenom: "Sophie" },
+];
+
+export const modules: Module[] = [
+  { id: "JIN702C", nom: "Optimisation" },
+  { id: "JIN703C", nom: "Informatique" },
+  { id: "JIN704C", nom: "Physique" },
+];
+
+export const notes: Note[] = [
+  { note: 15.5, numEtud: 21212006, idModule: "JIN702C" },
+  { note: 12.0, numEtud: 21212006, idModule: "JIN703C" },
+  { note: 18.0, numEtud: 21212007, idModule: "JIN702C" },
+  { note: 9.0, numEtud: 21212008, idModule: "JIN704C" },
+];
+
+export const ues: UE[] = [
+  { id: 1, nom: "UE Informatique" },
+  { id: 2, nom: "UE Mathématiques" },
+];
+
+export const ueModules: UeModule[] = [
+  { idModule: "JIN702C", idUE: 1, idPromo: "4AFISE25/26", coeff: 3.0 },
+  { idModule: "JIN703C", idUE: 2, idPromo: "4AFISE25/26", coeff: 4.0 },
+  { idModule: "JIN704C", idUE: 1, idPromo: "3AFISE25/26", coeff: 2.0 },
+];
+
+export const enseignements: Enseignement[] = [
+  { idProf: 1, idModule: "JIN702C", idPromo: "4AFISE25/26" },
+  { idProf: 2, idModule: "JIN703C", idPromo: "4AFISE25/26" },
+  { idProf: 1, idModule: "JIN704C", idPromo: "3AFISE25/26" },
+];
+
+export const ajustements: Ajustement[] = [
+  { numEtud: 21212006, idUE: 1, valeur: 13.25 },
+  { numEtud: 21212008, idUE: 1, valeur: 11.0 },
+];
+
+// --- Réponses d'erreur standard ---
+
+export const ERROR_NOT_FOUND: ApiError = { error: "Ressource introuvable" };
+export const ERROR_CONFLICT: ApiError = { error: "Ressource déjà existante" };
+export const ERROR_BAD_REQUEST: ApiError = { error: "Requête invalide" };
+export const ERROR_UNAUTHORIZED: ApiError = { error: "Non authentifié" };
+export const ERROR_FORBIDDEN: ApiError = { error: "Accès interdit" };
diff --git a/tests/helpers/render.ts b/tests/helpers/render.ts
new file mode 100644
index 0000000..f87b1d9
--- /dev/null
+++ b/tests/helpers/render.ts
@@ -0,0 +1,55 @@
+// Setup happy-dom + wrapper render pour les tests de composants Preact
+
+import { Window } from "happy-dom";
+
+let _window: Window | null = null;
+
+/**
+ * Initialise un environnement DOM virtuel via happy-dom.
+ * À appeler avant de rendre des composants Preact dans les tests.
+ */
+export function setupDOM(): void {
+  _window = new Window({ url: "http://localhost" });
+
+  // Expose les globals DOM nécessaires à Preact
+  const globals = _window as unknown as Record<string, unknown>;
+  const target = globalThis as unknown as Record<string, unknown>;
+
+  for (
+    const key of [
+      "document",
+      "navigator",
+      "location",
+      "HTMLElement",
+      "HTMLInputElement",
+      "HTMLTextAreaElement",
+      "HTMLSelectElement",
+      "Event",
+      "CustomEvent",
+      "KeyboardEvent",
+      "MouseEvent",
+      "InputEvent",
+      "MutationObserver",
+      "requestAnimationFrame",
+      "cancelAnimationFrame",
+    ]
+  ) {
+    target[key] = globals[key];
+  }
+
+  target["window"] = _window;
+}
+
+/**
+ * Nettoie l'environnement DOM.
+ * À appeler dans un afterEach ou à la fin d'un test.
+ */
+export function cleanupDOM(): void {
+  if (_window) {
+    const doc = _window.document;
+    doc.body.innerHTML = "";
+    doc.head.innerHTML = "";
+    _window.close();
+    _window = null;
+  }
+}
diff --git a/tests/integration/.gitkeep b/tests/integration/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/tests/unit/example_test.ts b/tests/unit/example_test.ts
new file mode 100644
index 0000000..86618ec
--- /dev/null
+++ b/tests/unit/example_test.ts
@@ -0,0 +1,266 @@
+import { assertEquals, assertExists } from "@std/assert";
+import { getFetchCalls, mockFetch, restoreFetch } from "../helpers/api_mock.ts";
+import { createMockDb } from "../helpers/db_mock.ts";
+import {
+  ERROR_CONFLICT,
+  ERROR_NOT_FOUND,
+  modules,
+  notes,
+  type Student,
+  students,
+} from "../helpers/fixtures.ts";
+import { cleanupDOM, setupDOM } from "../helpers/render.ts";
+
+// --- Fixtures ---
+
+Deno.test("fixtures - students match API shape", () => {
+  assertEquals(students.length, 3);
+  assertEquals(students[0].numEtud, 21212006);
+  assertEquals(students[0].idPromo, "4AFISE25/26");
+  assertEquals(typeof students[0].idPromo, "string");
+});
+
+Deno.test("fixtures - modules have string ids", () => {
+  assertEquals(modules[0].id, "JIN702C");
+  assertEquals(typeof modules[0].id, "string");
+});
+
+Deno.test("fixtures - notes use decimal values", () => {
+  assertEquals(notes[0].note, 15.5);
+  assertEquals(notes[0].idModule, "JIN702C");
+});
+
+// --- Mock fetch simple (GET 200) ---
+
+Deno.test("mockFetch - GET returns mocked data", async () => {
+  mockFetch({ "/students": students });
+  try {
+    const res = await fetch("http://localhost/api/students");
+    assertEquals(res.status, 200);
+    const data = await res.json();
+    assertEquals(data.length, 3);
+    assertEquals(data[0].nom, "Dupont");
+  } finally {
+    restoreFetch();
+  }
+});
+
+Deno.test("mockFetch - returns 404 for unknown routes", async () => {
+  mockFetch({});
+  try {
+    const res = await fetch("http://localhost/api/unknown");
+    assertEquals(res.status, 404);
+  } finally {
+    restoreFetch();
+  }
+});
+
+// --- Mock fetch avancé (méthodes + status codes) ---
+
+Deno.test("mockFetch - POST 201 created", async () => {
+  const newStudent = students[0];
+  mockFetch({
+    "/students": { method: "POST", status: 201, body: newStudent },
+  });
+  try {
+    const res = await fetch("http://localhost/api/students", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify(newStudent),
+    });
+    assertEquals(res.status, 201);
+    const data = await res.json();
+    assertEquals(data.numEtud, 21212006);
+  } finally {
+    restoreFetch();
+  }
+});
+
+Deno.test("mockFetch - DELETE 204 no content", async () => {
+  mockFetch({
+    "/students/21212006": { method: "DELETE", status: 204 },
+  });
+  try {
+    const res = await fetch("http://localhost/api/students/21212006", {
+      method: "DELETE",
+    });
+    assertEquals(res.status, 204);
+    assertEquals(res.body, null);
+  } finally {
+    restoreFetch();
+  }
+});
+
+Deno.test("mockFetch - 404 error response", async () => {
+  mockFetch({
+    "/students/99999": { status: 404, body: ERROR_NOT_FOUND },
+  });
+  try {
+    const res = await fetch("http://localhost/api/students/99999");
+    assertEquals(res.status, 404);
+    const data = await res.json();
+    assertEquals(data.error, "Ressource introuvable");
+  } finally {
+    restoreFetch();
+  }
+});
+
+Deno.test("mockFetch - 409 conflict", async () => {
+  mockFetch({
+    "/enseignements": { method: "POST", status: 409, body: ERROR_CONFLICT },
+  });
+  try {
+    const res = await fetch("http://localhost/api/enseignements", {
+      method: "POST",
+      body: JSON.stringify({
+        idProf: 1,
+        idModule: "JIN702C",
+        idPromo: "4AFISE25/26",
+      }),
+    });
+    assertEquals(res.status, 409);
+  } finally {
+    restoreFetch();
+  }
+});
+
+// --- getFetchCalls ---
+
+Deno.test("getFetchCalls - tracks all intercepted calls", async () => {
+  mockFetch({ "/notes": notes });
+  try {
+    await fetch("http://localhost/api/notes");
+    await fetch("http://localhost/api/notes?numEtud=21212006");
+    const calls = getFetchCalls();
+    assertEquals(calls.length, 2);
+    assertEquals(calls[0].method, "GET");
+    assertEquals(calls[1].url, "http://localhost/api/notes?numEtud=21212006");
+  } finally {
+    restoreFetch();
+  }
+});
+
+Deno.test("getFetchCalls - captures POST body", async () => {
+  mockFetch({ "/notes": { method: "POST", status: 201, body: notes[0] } });
+  try {
+    await fetch("http://localhost/api/notes", {
+      method: "POST",
+      body: JSON.stringify(notes[0]),
+    });
+    const calls = getFetchCalls();
+    assertEquals(calls.length, 1);
+    assertEquals(calls[0].method, "POST");
+    assertEquals((calls[0].body as { note: number }).note, 15.5);
+  } finally {
+    restoreFetch();
+  }
+});
+
+// --- Mock DB ---
+
+Deno.test("mockDb - getTable returns seeded rows", () => {
+  const db = createMockDb({ tables: { students: [...students] } });
+  assertEquals(db.getTable("students").length, 3);
+});
+
+Deno.test("mockDb - findOne by key", () => {
+  const db = createMockDb({ tables: { students: [...students] } });
+  const found = db.findOne<Student>("students", (r) => r.numEtud === 21212006);
+  assertExists(found);
+  assertEquals(found.nom, "Dupont");
+});
+
+Deno.test("mockDb - findOne returns undefined for missing", () => {
+  const db = createMockDb({ tables: { students: [...students] } });
+  const found = db.findOne<Student>("students", (r) => r.numEtud === 99999);
+  assertEquals(found, undefined);
+});
+
+Deno.test("mockDb - insert adds a row", () => {
+  const db = createMockDb({ tables: { students: [] } });
+  const newStudent: Student = {
+    numEtud: 21212099,
+    nom: "Test",
+    prenom: "User",
+    idPromo: "4AFISE25/26",
+  };
+  db.insert("students", newStudent);
+  assertEquals(db.getTable("students").length, 1);
+  assertEquals(
+    db.findOne<Student>("students", (r) => r.numEtud === 21212099)?.nom,
+    "Test",
+  );
+});
+
+Deno.test("mockDb - updateWhere modifies matching rows", () => {
+  const db = createMockDb({ tables: { students: [...students] } });
+  const updated = db.updateWhere<Student>(
+    "students",
+    (r) => r.numEtud === 21212006,
+    { prenom: "Marie" },
+  );
+  assertEquals(updated, 1);
+  assertEquals(
+    db.findOne<Student>("students", (r) => r.numEtud === 21212006)?.prenom,
+    "Marie",
+  );
+});
+
+Deno.test("mockDb - deleteWhere removes matching rows", () => {
+  const db = createMockDb({ tables: { students: [...students] } });
+  const deleted = db.deleteWhere<Student>(
+    "students",
+    (r) => r.numEtud === 21212006,
+  );
+  assertEquals(deleted, 1);
+  assertEquals(db.getTable("students").length, 2);
+});
+
+Deno.test("mockDb - findMany with filter", () => {
+  const db = createMockDb({ tables: { students: [...students] } });
+  const promo4 = db.findMany<Student>(
+    "students",
+    (r) => r.idPromo === "4AFISE25/26",
+  );
+  assertEquals(promo4.length, 2);
+});
+
+Deno.test("mockDb - reset clears all tables", () => {
+  const db = createMockDb({
+    tables: { students: [...students], notes: [...notes] },
+  });
+  db.reset();
+  assertEquals(db.getTable("students").length, 0);
+  assertEquals(db.getTable("notes").length, 0);
+});
+
+Deno.test("mockDb - isolated between instances", () => {
+  const db1 = createMockDb({ tables: { students: [...students] } });
+  const db2 = createMockDb({ tables: { students: [...students] } });
+  db1.deleteWhere<Student>("students", () => true);
+  assertEquals(db1.getTable("students").length, 0);
+  assertEquals(db2.getTable("students").length, 3);
+});
+
+// --- happy-dom ---
+
+Deno.test({
+  name: "happy-dom - document is available after setup",
+  sanitizeResources: false,
+  sanitizeOps: false,
+  fn() {
+    setupDOM();
+    try {
+      const doc = globalThis.document;
+      assertExists(doc);
+
+      const div = doc.createElement("div");
+      div.textContent = "hello";
+      doc.body.appendChild(div);
+
+      assertEquals(doc.body.textContent, "hello");
+    } finally {
+      cleanupDOM();
+    }
+  },
+});