test(HistoricalTrendView-mock-integrations): verify Asynchronous Service Layer Mocking & Local Cache Stubs (Variation 9) JhaSourav07#2681

Author: Mohammedsami001

components/dashboard/HistoricalTrendView.mock-integrations.test.tsx

@@ -0,0 +1,190 @@
+import React, { useState, useEffect } from 'react';
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { render, screen, waitFor } from '@testing-library/react';
+import HistoricalTrendView from './HistoricalTrendView';
+import type { ActivityData } from '@/types/dashboard';
+
+// Stub DOM observers missing in JSDOM
+global.ResizeObserver = class ResizeObserver {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+};
+
+global.IntersectionObserver = class IntersectionObserver {
+  readonly root: Element | Document | null = null;
+  readonly rootMargin: string = '';
+  readonly thresholds: ReadonlyArray<number> = [];
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+  takeRecords() {
+    return [];
+  }
+};
+
+const defaultPeriod = { kind: 'year' as const, year: '2023', from: '', to: '', label: '2023' };
+
+// Global cache stub
+const globalCache: Record<string, ActivityData[]> = {};
+
+// Mock Database stub
+class MockDatabase {
+  async fetchActivity(_username: string): Promise<ActivityData[]> {
+    // To be mocked per test
+    return [];
+  }
+}
+
+const mockDb = new MockDatabase();
+
+// Async Wrapper to simulate the Service Layer Mocking & Local Cache
+function AsyncTrendWrapper({ username }: { username: string }) {
+  const [data, setData] = useState<ActivityData[] | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    let isMounted = true;
+    const fetchData = async () => {
+      setLoading(true);
+      setError(null);
+
+      // Local cache layer query
+      if (globalCache[username]) {
+        if (isMounted) {
+          setData(globalCache[username]);
+          setLoading(false);
+        }
+        return;
+      }
+
+      // Database retrieval
+      try {
+        const response = await mockDb.fetchActivity(username);
+        // Complete cache sync
+        globalCache[username] = response;
+        if (isMounted) {
+          setData(response);
+        }
+      } catch (e: unknown) {
+        if (isMounted) {
+          setError(e instanceof Error ? e.message : 'Error occurred');
+        }
+      } finally {
+        if (isMounted) {
+          setLoading(false);
+        }
+      }
+    };
+
+    fetchData();
+    return () => {
+      isMounted = false;
+    };
+  }, [username]);
+
+  if (loading) return <div data-testid="pending-overlay">Loading Activity Data...</div>;
+  if (error) return <div data-testid="fallback-error">{error}</div>;
+  if (!data) return null;
+
+  return <HistoricalTrendView username={username} activity={data} period={defaultPeriod} />;
+}
+
+// Mock next/navigation
+vi.mock('next/navigation', () => ({
+  useRouter: () => ({
+    push: vi.fn(),
+  }),
+}));
+
+describe('HistoricalTrendView - Asynchronous Service Layer Mocking & Local Cache Stubs', () => {
+  let fetchSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    // Clear cache
+    for (const key in globalCache) delete globalCache[key];
+    fetchSpy = vi.spyOn(mockDb, 'fetchActivity');
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('1. Mock standard asynchronous imports and databases using stubs', async () => {
+    const mockData = [{ date: '2023-01-01', count: 5, intensity: 1 as const }];
+    fetchSpy.mockResolvedValue(mockData);
+
+    render(<AsyncTrendWrapper username="user1" />);
+
+    await waitFor(() => {
+      expect(screen.queryByTestId('pending-overlay')).not.toBeInTheDocument();
+    });
+
+    expect(fetchSpy).toHaveBeenCalledWith('user1');
+    expect(screen.getByText('2023 · 1 days')).toBeInTheDocument(); // Component rendered correctly
+  });
+
+  it('2. Test service loading paths to ensure pending state overlays render', () => {
+    // Never resolve to keep loading forever
+    fetchSpy.mockImplementation(() => new Promise(() => {}));
+
+    render(<AsyncTrendWrapper username="user2" />);
+
+    // Assert pending state immediately
+    expect(screen.getByTestId('pending-overlay')).toBeInTheDocument();
+    expect(screen.getByText('Loading Activity Data...')).toBeInTheDocument();
+  });
+
+  it('3. Assert local cache layers are queried before triggering database retrievals', async () => {
+    const cachedData = [{ date: '2023-02-01', count: 10, intensity: 2 as const }];
+    globalCache['cachedUser'] = cachedData;
+
+    render(<AsyncTrendWrapper username="cachedUser" />);
+
+    // Wait for the component to settle
+    await waitFor(() => {
+      expect(screen.getByText('2023 · 1 days')).toBeInTheDocument();
+    });
+
+    // Database retrieval should NOT be triggered
+    expect(fetchSpy).not.toHaveBeenCalled();
+    // Verify it rendered the cached data (active days = 1, streaks = 1)
+    expect(screen.getAllByText('1', { selector: 'p.text-3xl' })).toHaveLength(3);
+  });
+
+  it('4. Verify correct fallback procedures during fake endpoint timeout blocks', async () => {
+    const timeoutError = new Error('Database connection timed out');
+    fetchSpy.mockRejectedValue(timeoutError);
+
+    render(<AsyncTrendWrapper username="user-timeout" />);
+
+    // Initially loading
+    expect(screen.getByTestId('pending-overlay')).toBeInTheDocument();
+
+    // Fallback UI replaces loading overlay
+    await waitFor(() => {
+      expect(screen.getByTestId('fallback-error')).toBeInTheDocument();
+    });
+
+    expect(screen.queryByTestId('pending-overlay')).not.toBeInTheDocument();
+    expect(screen.getByText('Database connection timed out')).toBeInTheDocument();
+  });
+
+  it('5. Assert complete cache sync is written on success callbacks', async () => {
+    const freshData = [{ date: '2023-03-01', count: 20, intensity: 3 as const }];
+    fetchSpy.mockResolvedValue(freshData);
+
+    // Initial cache is empty
+    expect(globalCache['syncUser']).toBeUndefined();
+
+    render(<AsyncTrendWrapper username="syncUser" />);
+
+    await waitFor(() => {
+      expect(screen.queryByTestId('pending-overlay')).not.toBeInTheDocument();
+    });
+
+    // Cache sync was written successfully
+    expect(globalCache['syncUser']).toEqual(freshData);
+  });
+});