Improve code coverage for cli package (#13724)

packages/cli/src/core/auth.test.ts

@@ -0,0 +1,56 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { performInitialAuth } from './auth.js';
+import { type Config } from '@google/gemini-cli-core';
+
+vi.mock('@google/gemini-cli-core', () => ({
+  AuthType: {
+    OAUTH: 'oauth',
+  },
+  getErrorMessage: (e: unknown) => (e as Error).message,
+}));
+
+const AuthType = {
+  OAUTH: 'oauth',
+} as const;
+
+describe('auth', () => {
+  let mockConfig: Config;
+
+  beforeEach(() => {
+    mockConfig = {
+      refreshAuth: vi.fn(),
+    } as unknown as Config;
+  });
+
+  it('should return null if authType is undefined', async () => {
+    const result = await performInitialAuth(mockConfig, undefined);
+    expect(result).toBeNull();
+    expect(mockConfig.refreshAuth).not.toHaveBeenCalled();
+  });
+
+  it('should return null on successful auth', async () => {
+    const result = await performInitialAuth(
+      mockConfig,
+      AuthType.OAUTH as unknown as Parameters<typeof performInitialAuth>[1],
+    );
+    expect(result).toBeNull();
+    expect(mockConfig.refreshAuth).toHaveBeenCalledWith(AuthType.OAUTH);
+  });
+
+  it('should return error message on failed auth', async () => {
+    const error = new Error('Auth failed');
+    vi.mocked(mockConfig.refreshAuth).mockRejectedValue(error);
+    const result = await performInitialAuth(
+      mockConfig,
+      AuthType.OAUTH as unknown as Parameters<typeof performInitialAuth>[1],
+    );
+    expect(result).toBe('Failed to login. Message: Auth failed');
+    expect(mockConfig.refreshAuth).toHaveBeenCalledWith(AuthType.OAUTH);
+  });
+});