feat: phase 3 for git integration

tests/renderer/components/GitDiffView.test.tsx

@@ -0,0 +1,45 @@
+import React from 'react';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { GitDiffView } from '../../../src/renderer/components/GitDiffView/GitDiffView';
+import { useAppStore } from '../../../src/renderer/store';
+
+describe('GitDiffView', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+
+    useAppStore.setState({
+      activeProject: {
+        id: 'project-1',
+        name: 'Test Project',
+        slug: 'test-project',
+        isActive: true,
+        dataPath: '/repo/path',
+        createdAt: new Date().toISOString(),
+        updatedAt: new Date().toISOString(),
+      },
+    });
+
+    (window as any).electronAPI = {
+      ...(window as any).electronAPI,
+      git: {
+        ...(window as any).electronAPI?.git,
+        getDiff: vi.fn().mockResolvedValue({
+          filePath: 'posts/first.md',
+          patch: 'diff --git a/posts/first.md b/posts/first.md\n+hello',
+        }),
+      },
+      app: {
+        ...(window as any).electronAPI?.app,
+        getDefaultProjectPath: vi.fn().mockResolvedValue('/repo/path'),
+      },
+    };
+  });
+
+  it('loads and renders the git diff patch for the selected file', async () => {
+    render(<GitDiffView filePath="posts/first.md" />);
+
+    expect(await screen.findByText(/diff --git a\/posts\/first\.md b\/posts\/first\.md/i)).toBeInTheDocument();
+    expect((window as any).electronAPI.git.getDiff).toHaveBeenCalledWith('/repo/path', 'posts/first.md');
+  });
+});