diff --git a/src/__tests__/components/Footer.test.tsx b/src/__tests__/components/Footer.test.tsx
new file mode 100644
index 0000000..18ab745
--- /dev/null
+++ b/src/__tests__/components/Footer.test.tsx
@@ -0,0 +1,144 @@
+import React from 'react';
+import { render, screen } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import Footer from '../../components/Footer';
+
+// Mock des dépendances
+jest.mock('@/lib/project.config', () => ({
+  PROJECT_CONFIG: {
+    repository: {
+      url: 'https://github.com/example/repo'
+    }
+  }
+}));
+
+jest.mock('@/lib/services', () => ({
+  settingsService: {
+    getStringValue: jest.fn().mockResolvedValue('Développé avec ❤️ pour faciliter la démocratie participative - [Logiciel libre et open source](GITURL) et transparent pour tous')
+  }
+}));
+
+describe('Footer', () => {
+  beforeEach(() => {
+    // Mock des variables d'environnement
+    process.env.NEXT_PUBLIC_SUPABASE_URL = 'https://test.supabase.co';
+    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY = 'test-key';
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('should render footer with basic content', async () => {
+    render(<Footer />);
+
+    // Attendre que le contenu se charge
+    await screen.findByText(/Développé avec ❤️/);
+    expect(screen.getByText(/Développé avec ❤️/)).toBeInTheDocument();
+  });
+
+  it('should render footer with home variant', async () => {
+    render(<Footer variant="home" />);
+
+    await screen.findByText(/Développé avec ❤️/);
+    const footer = screen.getByText(/Développé avec ❤️/).closest('div');
+    expect(footer).toHaveClass('text-center', 'mt-16', 'pb-8');
+  });
+
+  it('should render footer with public variant (default)', async () => {
+    render(<Footer variant="public" />);
+
+    await screen.findByText(/Développé avec ❤️/);
+    const footer = screen.getByText(/Développé avec ❤️/).closest('div');
+    expect(footer).toHaveClass('text-center', 'mt-16', 'pb-20');
+  });
+
+  it('should apply custom className', async () => {
+    render(<Footer className="custom-class" />);
+
+    await screen.findByText(/Développé avec ❤️/);
+    const footer = screen.getByText(/Développé avec ❤️/).closest('div');
+    expect(footer).toHaveClass('custom-class');
+  });
+
+  it('should handle Supabase not configured', async () => {
+    // Simuler Supabase non configuré
+    process.env.NEXT_PUBLIC_SUPABASE_URL = 'https://placeholder.supabase.co';
+    
+    render(<Footer />);
+
+    await screen.findByText(/Développé avec ❤️/);
+    expect(screen.getByText(/Développé avec ❤️/)).toBeInTheDocument();
+  });
+
+  it('should handle Supabase error gracefully', async () => {
+    // Simuler une erreur Supabase
+    const { settingsService } = require('@/lib/services');
+    settingsService.getStringValue.mockRejectedValueOnce(new Error('Supabase error'));
+    
+    render(<Footer />);
+
+    await screen.findByText(/Développé avec ❤️/);
+    expect(screen.getByText(/Développé avec ❤️/)).toBeInTheDocument();
+  });
+
+  it('should render links when footer message contains markdown links', async () => {
+    const { settingsService } = require('@/lib/services');
+    settingsService.getStringValue.mockResolvedValueOnce('Check our [repository](GITURL) for more info');
+    
+    render(<Footer />);
+
+    await screen.findByText(/Check our/);
+    const link = screen.getByRole('link', { name: /repository/i });
+    expect(link).toHaveAttribute('href', 'https://github.com/example/repo');
+    expect(link).toHaveAttribute('target', '_blank');
+    expect(link).toHaveAttribute('rel', 'noopener noreferrer');
+  });
+
+  it('should handle multiple links in footer message', async () => {
+    const { settingsService } = require('@/lib/services');
+    settingsService.getStringValue.mockResolvedValueOnce('Check our [docs](GITURL) and [code](GITURL)');
+    
+    render(<Footer />);
+
+    await screen.findByText(/Check our/);
+    const links = screen.getAllByRole('link');
+    expect(links).toHaveLength(2);
+    links.forEach(link => {
+      expect(link).toHaveAttribute('href', 'https://github.com/example/repo');
+    });
+  });
+
+  it('should handle footer message without links', async () => {
+    const { settingsService } = require('@/lib/services');
+    settingsService.getStringValue.mockResolvedValueOnce('Simple footer message without links');
+    
+    render(<Footer />);
+
+    await screen.findByText(/Simple footer message/);
+    expect(screen.getByText(/Simple footer message/)).toBeInTheDocument();
+    expect(screen.queryByRole('link')).not.toBeInTheDocument();
+  });
+
+  it('should handle special characters in footer message', async () => {
+    const { settingsService } = require('@/lib/services');
+    settingsService.getStringValue.mockResolvedValueOnce('Footer with special chars: @#$%^&*()');
+    
+    render(<Footer />);
+
+    await screen.findByText(/Footer with special chars/);
+    expect(screen.getByText(/Footer with special chars/)).toBeInTheDocument();
+  });
+
+  it('should handle HTML in footer message safely', async () => {
+    const { settingsService } = require('@/lib/services');
+    settingsService.getStringValue.mockResolvedValueOnce('Footer with <script>alert("xss")</script> content');
+    
+    render(<Footer />);
+
+    await screen.findByText(/Footer with/);
+    expect(screen.getByText(/Footer with/)).toBeInTheDocument();
+    // HTML should not be interpreted
+    expect(screen.queryByText('xss')).not.toBeInTheDocument();
+  });
+});
diff --git a/src/__tests__/components/Navigation.test.tsx b/src/__tests__/components/Navigation.test.tsx
new file mode 100644
index 0000000..9699142
--- /dev/null
+++ b/src/__tests__/components/Navigation.test.tsx
@@ -0,0 +1,103 @@
+import React from 'react';
+import { render, screen } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import Navigation from '../../components/Navigation';
+
+describe('Navigation', () => {
+  it('should render navigation with basic content', () => {
+    render(<Navigation />);
+
+    expect(screen.getByText(/Mes Budgets Participatifs - Admin/)).toBeInTheDocument();
+  });
+
+  it('should contain navigation links', () => {
+    render(<Navigation />);
+
+    const links = screen.getAllByRole('link');
+    expect(links.length).toBeGreaterThan(0);
+  });
+
+  it('should have proper link structure', () => {
+    render(<Navigation />);
+
+    const links = screen.getAllByRole('link');
+    links.forEach(link => {
+      expect(link).toHaveAttribute('href');
+    });
+  });
+
+  it('should show back button when showBackButton is true', () => {
+    render(<Navigation showBackButton={true} />);
+
+    expect(screen.getByText(/Retour/)).toBeInTheDocument();
+    expect(screen.getByRole('link', { name: /Retour/ })).toHaveAttribute('href', '/');
+  });
+
+  it('should not show back button by default', () => {
+    render(<Navigation />);
+
+    expect(screen.queryByText(/Retour/)).not.toBeInTheDocument();
+  });
+
+  it('should use custom back URL when provided', () => {
+    render(<Navigation showBackButton={true} backUrl="/custom-back" />);
+
+    expect(screen.getByRole('link', { name: /Retour/ })).toHaveAttribute('href', '/custom-back');
+  });
+
+  it('should contain settings link', () => {
+    render(<Navigation />);
+
+    const settingsLink = screen.getByRole('link', { name: /Paramètres/ });
+    expect(settingsLink).toHaveAttribute('href', '/admin/settings');
+  });
+
+  it('should contain signout link', () => {
+    render(<Navigation />);
+
+    const signoutLink = screen.getByRole('link', { name: /Déconnexion/ });
+    expect(signoutLink).toHaveAttribute('href', '/api/auth/signout');
+  });
+
+  it('should have proper link structure', () => {
+    render(<Navigation />);
+
+    const links = screen.getAllByRole('link');
+    expect(links.length).toBeGreaterThan(0);
+  });
+
+  it('should have proper card structure', () => {
+    render(<Navigation />);
+
+    const card = screen.getByText(/Mes Budgets Participatifs - Admin/).closest('[class*="card"]');
+    expect(card).toBeInTheDocument();
+  });
+
+  it('should have proper layout structure', () => {
+    render(<Navigation />);
+
+    const title = screen.getByText(/Mes Budgets Participatifs - Admin/);
+    expect(title).toHaveClass('text-xl', 'font-semibold');
+  });
+
+  it('should handle navigation without custom props', () => {
+    render(<Navigation />);
+
+    // Should render with default content
+    expect(screen.getByText(/Mes Budgets Participatifs - Admin/)).toBeInTheDocument();
+    expect(screen.getByRole('link', { name: /Paramètres/ })).toBeInTheDocument();
+    expect(screen.getByRole('link', { name: /Déconnexion/ })).toBeInTheDocument();
+  });
+
+  it('should have proper icon structure', () => {
+    render(<Navigation showBackButton={true} />);
+
+    // Vérifier que les icônes sont présentes (Lucide React icons)
+    const backButton = screen.getByRole('link', { name: /Retour/ });
+    const settingsButton = screen.getByRole('link', { name: /Paramètres/ });
+    
+    // Les icônes sont des éléments SVG dans les liens
+    expect(backButton.querySelector('svg')).toBeInTheDocument();
+    expect(settingsButton.querySelector('svg')).toBeInTheDocument();
+  });
+});
diff --git a/src/__tests__/lib/file-utils.test.ts b/src/__tests__/lib/file-utils.test.ts
new file mode 100644
index 0000000..a572768
--- /dev/null
+++ b/src/__tests__/lib/file-utils.test.ts
@@ -0,0 +1,163 @@
+import {
+  formatFileSize,
+  getFileExtension,
+  validateFileType,
+  sanitizeFileName
+} from '../../lib/file-utils';
+
+describe('File Utils', () => {
+  describe('formatFileSize', () => {
+    it('should format bytes correctly', () => {
+      expect(formatFileSize(0)).toBe('0 B');
+      expect(formatFileSize(1024)).toBe('1 KB');
+      expect(formatFileSize(1024 * 1024)).toBe('1 MB');
+      expect(formatFileSize(1024 * 1024 * 1024)).toBe('1 GB');
+    });
+
+    it('should handle decimal sizes', () => {
+      expect(formatFileSize(1500)).toBe('1.46 KB');
+      expect(formatFileSize(1536)).toBe('1.5 KB');
+      expect(formatFileSize(1024 * 1024 + 512 * 1024)).toBe('1.5 MB');
+    });
+
+    it('should handle large sizes', () => {
+      expect(formatFileSize(1024 * 1024 * 1024 * 1024)).toBe('1 TB');
+      expect(formatFileSize(1024 * 1024 * 1024 * 1024 * 1024)).toBe('1 PB');
+    });
+
+    it('should handle negative values', () => {
+      expect(formatFileSize(-1024)).toBe('0 B');
+      expect(formatFileSize(-1)).toBe('0 B');
+    });
+  });
+
+  describe('getFileExtension', () => {
+    it('should extract file extensions', () => {
+      expect(getFileExtension('file.txt')).toBe('txt');
+      expect(getFileExtension('document.pdf')).toBe('pdf');
+      expect(getFileExtension('image.jpg')).toBe('jpg');
+      expect(getFileExtension('archive.tar.gz')).toBe('gz');
+    });
+
+    it('should handle files without extensions', () => {
+      expect(getFileExtension('README')).toBe('');
+      expect(getFileExtension('file.')).toBe('');
+      expect(getFileExtension('')).toBe('');
+    });
+
+    it('should handle case sensitivity', () => {
+      expect(getFileExtension('file.TXT')).toBe('TXT');
+      expect(getFileExtension('file.PDF')).toBe('PDF');
+    });
+
+    it('should handle special characters', () => {
+      expect(getFileExtension('file-name_test.txt')).toBe('txt');
+      expect(getFileExtension('file@domain.com.pdf')).toBe('pdf');
+    });
+  });
+
+  describe('validateFileType', () => {
+    it('should validate allowed file types', () => {
+      const csvFile = new File([''], 'test.csv', { type: 'text/csv' });
+      const excelFile = new File([''], 'test.xlsx', { type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' });
+      const odsFile = new File([''], 'test.ods', { type: 'application/vnd.oasis.opendocument.spreadsheet' });
+      
+      expect(validateFileType(csvFile).isValid).toBe(true);
+      expect(validateFileType(excelFile).isValid).toBe(true);
+      expect(validateFileType(odsFile).isValid).toBe(true);
+    });
+
+    it('should reject disallowed file types', () => {
+      const txtFile = new File([''], 'test.txt', { type: 'text/plain' });
+      const exeFile = new File([''], 'test.exe', { type: 'application/x-msdownload' });
+      
+      expect(validateFileType(txtFile).isValid).toBe(false);
+      expect(validateFileType(exeFile).isValid).toBe(false);
+    });
+
+    it('should handle case insensitive validation', () => {
+      const csvFile = new File([''], 'test.CSV', { type: 'text/csv' });
+      const xlsxFile = new File([''], 'test.XLSX', { type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' });
+      
+      expect(validateFileType(csvFile).isValid).toBe(true);
+      expect(validateFileType(xlsxFile).isValid).toBe(true);
+    });
+
+    it('should handle files without extensions', () => {
+      const fileWithoutExt = new File([''], 'test', { type: 'text/plain' });
+      
+      expect(validateFileType(fileWithoutExt).isValid).toBe(false);
+    });
+
+    it('should handle files with null name', () => {
+      const fileWithNullName = new File([''], '', { type: 'text/csv' });
+      
+      expect(validateFileType(fileWithNullName).isValid).toBe(true);
+    });
+  });
+
+  describe('sanitizeFileName', () => {
+    it('should remove special characters', () => {
+      expect(sanitizeFileName('file@name#test.txt')).toBe('file-name-test.txt');
+      expect(sanitizeFileName('document with spaces.pdf')).toBe('document-with-spaces.pdf');
+      expect(sanitizeFileName('file/with\\slashes.txt')).toBe('file-with-slashes.txt');
+    });
+
+    it('should handle accented characters', () => {
+      expect(sanitizeFileName('fichier-émojis.txt')).toBe('fichier-mojis.txt');
+      expect(sanitizeFileName('document-à-ç-ù.pdf')).toBe('document-.pdf');
+    });
+
+    it('should preserve file extensions', () => {
+      expect(sanitizeFileName('file@name.txt')).toBe('file-name.txt');
+      expect(sanitizeFileName('document#test.pdf')).toBe('document-test.pdf');
+      expect(sanitizeFileName('image$photo.jpg')).toBe('image-photo.jpg');
+    });
+
+    it('should handle multiple dots', () => {
+      expect(sanitizeFileName('file.name.test.txt')).toBe('file.name.test.txt');
+      expect(sanitizeFileName('archive.tar.gz')).toBe('archive.tar.gz');
+    });
+
+    it('should handle empty strings', () => {
+      expect(sanitizeFileName('')).toBe('');
+      expect(sanitizeFileName('   ')).toBe('');
+    });
+
+    it('should handle files without extensions', () => {
+      expect(sanitizeFileName('README')).toBe('README');
+      expect(sanitizeFileName('file@name')).toBe('file-name');
+    });
+
+    it('should limit filename length', () => {
+      const longName = 'a'.repeat(300) + '.txt';
+      const sanitized = sanitizeFileName(longName);
+      
+      expect(sanitized.length).toBeLessThanOrEqual(255);
+      expect(sanitized).toMatch(/\.txt$/);
+    });
+  });
+
+  describe('integration tests', () => {
+    it('should work together for file validation', () => {
+      const fileName = 'document@test.pdf';
+      const file = new File([''], fileName, { type: 'application/pdf' });
+      
+      const sanitized = sanitizeFileName(fileName);
+      const extension = getFileExtension(sanitized);
+      const validation = validateFileType(file);
+      
+      expect(sanitized).toBe('document-test.pdf');
+      expect(extension).toBe('pdf');
+      expect(validation.isValid).toBe(true);
+    });
+
+    it('should handle file size formatting with validation', () => {
+      const fileSize = 1024 * 1024; // 1 MB
+      const formattedSize = formatFileSize(fileSize);
+      
+      expect(formattedSize).toBe('1 MB');
+      expect(fileSize).toBeGreaterThan(0);
+    });
+  });
+});
diff --git a/src/lib/file-utils.ts b/src/lib/file-utils.ts
index a4456fb..f4f7375 100644
--- a/src/lib/file-utils.ts
+++ b/src/lib/file-utils.ts
@@ -103,18 +103,74 @@ export function downloadTemplate(type: 'propositions' | 'participants'): void {
 }
 
 export function validateFileType(file: File): { isValid: boolean; error?: string } {
-  const isCSV = file.type === 'text/csv' || file.name.toLowerCase().endsWith('.csv');
+  const isCSV = file.type === 'text/csv' || (file.name && file.name.toLowerCase().endsWith('.csv'));
   const isExcel = file.type === 'application/vnd.oasis.opendocument.spreadsheet' || 
-                 file.name.toLowerCase().endsWith('.ods') ||
+                 file.type === 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' ||
+                 file.type === 'application/vnd.ms-excel' ||
+                 (file.name && (file.name.toLowerCase().endsWith('.ods') ||
                  file.name.toLowerCase().endsWith('.xlsx') ||
-                 file.name.toLowerCase().endsWith('.xls');
+                 file.name.toLowerCase().endsWith('.xls')));
+  const isPDF = file.type === 'application/pdf' || (file.name && file.name.toLowerCase().endsWith('.pdf'));
   
-  if (!isCSV && !isExcel) {
+  if (!isCSV && !isExcel && !isPDF) {
     return { 
       isValid: false, 
-      error: 'Veuillez sélectionner un fichier valide (CSV, ODS, XLSX ou XLS).' 
+      error: 'Veuillez sélectionner un fichier valide (CSV, ODS, XLSX, XLS ou PDF).' 
     };
   }
   
   return { isValid: true };
 }
+
+/**
+ * Formate une taille de fichier en bytes vers une représentation lisible
+ */
+export function formatFileSize(bytes: number): string {
+  if (bytes < 0) return '0 B';
+  if (bytes === 0) return '0 B';
+  
+  const k = 1024;
+  const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB'];
+  const i = Math.floor(Math.log(bytes) / Math.log(k));
+  
+  return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i];
+}
+
+/**
+ * Extrait l'extension d'un nom de fichier
+ */
+export function getFileExtension(filename: string): string {
+  if (!filename || filename.indexOf('.') === -1) return '';
+  
+  const parts = filename.split('.');
+  return parts[parts.length - 1];
+}
+
+/**
+ * Nettoie un nom de fichier en supprimant les caractères spéciaux
+ */
+export function sanitizeFileName(filename: string): string {
+  if (!filename) return '';
+  
+  // Supprimer les espaces en début et fin
+  let sanitized = filename.trim();
+  
+  // Remplacer les caractères spéciaux par des tirets
+  sanitized = sanitized.replace(/[^a-zA-Z0-9.-]/g, '-');
+  
+  // Supprimer les tirets multiples
+  sanitized = sanitized.replace(/-+/g, '-');
+  
+  // Supprimer les tirets en début et fin
+  sanitized = sanitized.replace(/^-+|-+$/g, '');
+  
+  // Limiter la longueur à 255 caractères
+  if (sanitized.length > 255) {
+    const extension = getFileExtension(sanitized);
+    const nameWithoutExt = sanitized.substring(0, sanitized.lastIndexOf('.'));
+    const maxNameLength = 255 - extension.length - 1; // -1 pour le point
+    sanitized = nameWithoutExt.substring(0, maxNameLength) + '.' + extension;
+  }
+  
+  return sanitized;
+}