test(template): implement mock integrations and cache layer stubs

Author: shubhangisaxena953

app/template.mock-integrations.test.tsx

@@ -0,0 +1,130 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import React from 'react';
+import { render, screen } from '@testing-library/react';
+import Template from './template';
+
+// --- TYPED INTERFACES FOR MOCKED MODULES ---
+interface MockMongoDBModule {
+  connectToDatabase: () => Promise<string>;
+}
+
+interface MockGitHubModule {
+  fetchGitHubContributions: (username: string) => Promise<{
+    totalContributions: number;
+    syncStatus: string;
+  }>;
+}
+
+// --- MOCK INTEGRATIONS & STUBS ---
+vi.mock('@/lib/mongodb', () => ({
+  connectToDatabase: vi.fn().mockResolvedValue('Mocked DB Connection'),
+}));
+
+vi.mock('@/lib/github', () => ({
+  fetchGitHubContributions: vi
+    .fn()
+    .mockResolvedValue({ totalContributions: 100, syncStatus: 'SUCCESS' }),
+}));
+
+const mockCacheLayer = {
+  get: vi.fn(),
+  set: vi.fn(),
+};
+
+describe('AppTemplate Mock Integrations', () => {
+  beforeEach(() => {
+    vi.resetAllMocks();
+  });
+
+  // 1. Asynchronous Service Layer Mocking
+  it('mocks standard asynchronous imports and databases using stubs', async () => {
+    const mongodb = (await import('@/lib/mongodb')) as unknown as MockMongoDBModule;
+    const github = (await import('@/lib/github')) as unknown as MockGitHubModule;
+
+    const dbResult = await mongodb.connectToDatabase();
+    const githubResult = await github.fetchGitHubContributions('test-user');
+
+    expect(dbResult).toBe('Mocked DB Connection');
+    expect(githubResult.totalContributions).toBe(100);
+    expect(mongodb.connectToDatabase).toHaveBeenCalled();
+    expect(github.fetchGitHubContributions).toHaveBeenCalled();
+  });
+
+  // 2. Pending State Overlays & Service Loading Paths
+  it('renders pending state overlays during service loading paths', async () => {
+    const github = (await import('@/lib/github')) as unknown as MockGitHubModule;
+
+    // Create an explicitly unresolved promise to force the component to stay in a loading state
+    const infinitePendingPromise = new Promise<{ totalContributions: number; syncStatus: string }>(
+      () => {}
+    );
+    vi.mocked(github.fetchGitHubContributions).mockReturnValueOnce(infinitePendingPromise);
+
+    render(
+      <Template>
+        <div data-testid="loading-overlay">Syncing Monolith Skyline...</div>
+      </Template>
+    );
+
+    // Retrieve the element and use environment-agnostic assertions
+    const overlay = screen.getByTestId('loading-overlay');
+    expect(overlay).not.toBeNull();
+    expect(overlay.textContent).toContain('Syncing Monolith Skyline...');
+  });
+
+  // 3. Local Cache Evaluation Precedence
+  it('queries local cache layers before triggering database retrievals', async () => {
+    const mongodb = (await import('@/lib/mongodb')) as unknown as MockMongoDBModule;
+
+    mockCacheLayer.get.mockReturnValue({ cachedTotal: 100 });
+
+    let dbQueried = false;
+    const cachedData = mockCacheLayer.get('user_streak_data');
+
+    if (!cachedData) {
+      await mongodb.connectToDatabase();
+      dbQueried = true;
+    }
+
+    expect(mockCacheLayer.get).toHaveBeenCalledWith('user_streak_data');
+    expect(dbQueried).toBe(false);
+    expect(mongodb.connectToDatabase).not.toHaveBeenCalled();
+  });
+
+  // 4. Endpoint Timeout & Fallback Error Protocols
+  it('triggers correct fallback procedures during fake endpoint timeout blocks', async () => {
+    const github = (await import('@/lib/github')) as unknown as MockGitHubModule;
+
+    vi.mocked(github.fetchGitHubContributions).mockRejectedValueOnce(
+      new Error('TIMEOUT_GATEWAY_RESET')
+    );
+
+    let interfaceFallbackMessage = '';
+    try {
+      await github.fetchGitHubContributions('stale-user');
+    } catch (err) {
+      const error = err as Error;
+      expect(error.message).toBe('TIMEOUT_GATEWAY_RESET');
+      interfaceFallbackMessage = 'Connection timed out. Loading local offline landscape profiles.';
+    }
+
+    expect(interfaceFallbackMessage).toBe(
+      'Connection timed out. Loading local offline landscape profiles.'
+    );
+  });
+
+  // 5. Successful Commits & Cache Write Synchronization
+  it('writes complete cache sync on success callbacks', async () => {
+    const github = (await import('@/lib/github')) as unknown as MockGitHubModule;
+    const freshPayload = { totalContributions: 600, syncStatus: 'SUCCESS' };
+
+    vi.mocked(github.fetchGitHubContributions).mockResolvedValueOnce(freshPayload);
+    const result = await github.fetchGitHubContributions('active-contributor');
+
+    if (result.syncStatus === 'SUCCESS') {
+      mockCacheLayer.set('user_streak_data', result);
+    }
+
+    expect(mockCacheLayer.set).toHaveBeenCalledWith('user_streak_data', freshPayload);
+  });
+});