Add unit test.

jest.config.js

@@ -1,7 +1,7 @@
 module.exports = {
   preset: 'ts-jest',
   testEnvironment: 'node',
-  testMatch: ['<rootDir>/src/__tests__/unit/**/*.test.ts'],
+  testMatch: ['<rootDir>/tests/unit/**/*.test.ts'],
   automock: false,
   transform: {
     '^.+\\.ts$': [

tests/unit/extra_model_config.test.ts

@@ -0,0 +1,31 @@
+import { app } from 'electron';
+import path from 'path';
+import { getModelConfigPath } from '../../src/config/extra_model_config';
+
+// Mock electron
+jest.mock('electron', () => ({
+  app: {
+    getPath: jest.fn(),
+  },
+}));
+
+describe('getModelConfigPath', () => {
+  it('should return the correct path', async () => {
+    // Mock the userData path
+    const mockUserDataPath = '/fake/user/data';
+    (app.getPath as jest.Mock).mockImplementation((key: string) => {
+      if (key === 'userData') {
+        return mockUserDataPath;
+      }
+      throw new Error(`Unexpected getPath key: ${key}`);
+    });
+
+    const result = await getModelConfigPath();
+
+    // Verify the path is correctly joined
+    expect(result).toBe(path.join(mockUserDataPath, 'extra_model_paths.yaml'));
+
+    // Verify app.getPath was called with correct argument
+    expect(app.getPath).toHaveBeenCalledWith('userData');
+  });
+});