Add unit and integration tests for core modules and API routes

Unit tests for utils, crypto, rate-limit, env validation, and notification
prefs. Integration tests for health, tracks, and reactions API routes using
in-memory PGlite. Disable max-lines and no-explicit-any lint rules for test files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: GraysonCAdams

eslint.config.mjs

@@ -26,6 +26,13 @@ const eslintConfig = defineConfig([
       'max-lines': ['warn', { max: 300, skipBlankLines: true, skipComments: true }],
     },
   },
+  {
+    files: ['**/*.test.ts', 'src/test/**/*.ts'],
+    rules: {
+      'max-lines': 'off',
+      '@typescript-eslint/no-explicit-any': 'off',
+    },
+  },
 ]);
 
 export default eslintConfig;

src/app/api/health/route.test.ts

@@ -0,0 +1,48 @@
+import { describe, it, expect, vi, beforeAll, afterAll } from 'vitest';
+import { setupTestDb, teardownTestDb } from '@/test/db-setup';
+
+// Mock logger to suppress output
+vi.mock('@/lib/logger', () => ({
+  logger: { error: vi.fn(), warn: vi.fn(), info: vi.fn(), debug: vi.fn() },
+}));
+
+describe('GET /api/health', () => {
+  beforeAll(async () => {
+    const testDb = await setupTestDb();
+    vi.doMock('@/db', () => ({ db: testDb }));
+  });
+
+  afterAll(async () => {
+    await teardownTestDb();
+  });
+
+  it('returns 200 when DB is reachable', async () => {
+    const { GET } = await import('./route');
+    const response = await GET();
+    expect(response.status).toBe(200);
+    const data = await response.json();
+    expect(data.status).toBe('ok');
+  });
+
+  it('returns 503 when DB throws', async () => {
+    vi.doMock('@/db', () => ({
+      db: {
+        select: () => ({
+          from: () => ({
+            limit: () => {
+              throw new Error('connection refused');
+            },
+          }),
+        }),
+      },
+    }));
+
+    // Dynamic import picks up the new mock
+    const { GET } = await import('./route');
+    const response = await GET();
+    expect(response.status).toBe(503);
+    const data = await response.json();
+    expect(data.status).toBe('error');
+    expect(data.message).toBe('Database unreachable');
+  });
+});