🧪 Add missing error path test for loadFormats

.gitignore

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 __pycache__/
 *.pyc
+node_modules/

docs/index.test.js

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+const fs = require('fs');
+const path = require('path');
+
+describe('loadFormats Error Path', () => {
+    test('should populate fallback formats when fetch fails', async () => {
+        const html = fs.readFileSync(path.resolve(__dirname, 'index.html'), 'utf-8');
+
+        // Mock fetch to reject ONLY for format_database.json
+        global.fetch = jest.fn().mockImplementation((url) => {
+            if (url.includes('format_database.json')) {
+                return Promise.reject(new Error('Failed to fetch format database'));
+            }
+            // For the WASM fetch, just resolve it slowly or return a dummy buffer
+            return new Promise((resolve) => setTimeout(() => resolve({
+                arrayBuffer: () => Promise.resolve(new ArrayBuffer(0))
+            }), 2000));
+        });
+
+        // Mock URL methods
+        global.URL.createObjectURL = jest.fn();
+        global.URL.revokeObjectURL = jest.fn();
+
+        // Ensure DOM is empty first
+        document.body.innerHTML = '';
+
+        // Now set the innerHTML to our full HTML
+        document.documentElement.innerHTML = html;
+
+        // Get the script tag content
+        const scripts = document.querySelectorAll('script');
+        let mainScript = '';
+        scripts.forEach(script => {
+            if (!script.src && script.textContent.includes('loadFormats')) {
+                mainScript = script.textContent;
+            }
+        });
+
+        // Remove import statements since eval doesn't support them in this context
+        mainScript = mainScript.replace(/import\s+.*?from\s+['"].*?['"];?/g, '');
+
+        global.initializeImageMagick = jest.fn().mockResolvedValue();
+        global.MagickFormat = {};
+
+        // Execute the script
+        eval(mainScript);
+
+        // Let the promises resolve (specifically the rejected fetch for format_database)
+        await new Promise(resolve => setTimeout(resolve, 50));
+
+        const targetFormatSelect = document.getElementById('targetFormat');
+        const fileInput = document.getElementById('fileInput');
+        const statusDiv = document.getElementById('status');
+
+        expect(statusDiv.textContent).toBe("Failed to load format database. Defaulting to basic formats.");
+
+        const options = targetFormatSelect.querySelectorAll('option');
+        expect(options.length).toBe(4);
+        expect(options[0].value).toBe('png');
+        expect(options[1].value).toBe('jpg');
+        expect(options[2].value).toBe('webp');
+        expect(options[3].value).toBe('pdf');
+
+        expect(fileInput.accept).toBe('.png,.jpg,.jpeg,.webp,.pdf');
+    });
+});

jest.config.js

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+module.exports = {
+    testEnvironment: 'jest-environment-jsdom'
+};