# Testing Improvements Design

**Date:** 2026-04-03
**Scope:** Unit tests for new server code + Playwright E2E test setup with seeded database

## Part 1: Unit/Integration Tests (Bun test runner)

### tests/lib/params.test.ts

Tests for `parseId` helper in `src/server/lib/params.ts`:
- Valid positive integers (1, 42, 999) return the number
- Zero returns null
- Negative numbers (-1, -100) return null
- Decimals (1.5, 3.14) return null
- Non-numeric strings ("abc", "", "hello") return null
- NaN-producing values return null

### tests/middleware/rateLimit.test.ts

Tests for rate limiter in `src/server/middleware/rateLimit.ts`:
- First request passes through (200)
- 5 requests succeed, 6th returns 429
- 429 response includes `Retry-After` header
- Different IPs tracked independently
- After window expires, requests succeed again

Since the rate limiter uses a module-level `Map`, tests need to either:
- Reset the store between tests (export a `resetStore` for testing), OR
- Use unique paths/IPs per test to avoid interference

Recommended: export a `_resetForTesting()` function from rateLimit.ts that clears the store. Only used in tests.

### tests/routes/params.test.ts

Route-level integration tests verifying 400 responses for invalid IDs:
- `GET /api/items/abc` → 400
- `GET /api/items/-1` → 400
- `GET /api/items/0` → 400
- `DELETE /api/categories/notanumber` → 400
- `GET /api/threads/abc` → 400
- `GET /api/setups/abc` → 400

Uses existing test app pattern with in-memory DB.

## Part 2: Playwright E2E Setup

### Installation

- `bun add -d @playwright/test`
- `bunx playwright install chromium` (only Chromium needed)

### Configuration: playwright.config.ts

```ts
export default defineConfig({
  testDir: "./e2e",
  webServer: {
    command: "DATABASE_PATH=./e2e/test.db bun run dev:server",
    port: 3000,
    reuseExistingServer: !process.env.CI,
  },
  use: {
    baseURL: "http://localhost:3000",
  },
  projects: [{ name: "chromium", use: { ...devices["Desktop Chrome"] } }],
});
```

### Database Seeding: e2e/seed.ts

Script that creates `e2e/test.db` with:
- Run Drizzle migrations against the file
- Seed data:
  - 1 user (username: "admin", password: "password123")
  - 3 categories: Shelter, Sleep System, Cook Kit
  - 6 items across categories with realistic weights/prices
  - 1 active thread with 3 candidates (with pros/cons, sort_order)
  - 1 resolved thread
  - 1 setup with 4 items (mixed classifications)
  - Settings: weightUnit=g, currency=USD, onboardingComplete=true

Run before E2E tests via `e2e/global-setup.ts` (Playwright globalSetup).

### E2E Test Files

**e2e/dashboard.spec.ts**
- Dashboard page loads
- Summary cards show item count, weight, cost
- Navigation links to collection work

**e2e/collection.spec.ts**
- Gear tab renders items grouped by category
- Search input filters items by name
- Category filter dropdown works
- Tab switching between gear/planning/setups

**e2e/threads.spec.ts**
- Thread detail page loads with candidates
- Comparison view toggle works (shows table)
- Rank badges visible on candidates

**e2e/auth.spec.ts**
- Login page renders
- Login with valid credentials succeeds
- Login with wrong password shows error
- Rate limiting returns error after 5 attempts

**e2e/error-boundary.spec.ts**
- App doesn't white-screen on unknown routes
- Navigating to a non-existent thread/setup shows appropriate error

### Scripts

Add to package.json:
- `"test:e2e": "bunx playwright test"`
- `"test:e2e:ui": "bunx playwright test --ui"` (for debugging)

### Files to .gitignore

- `e2e/test.db`
- `test-results/`
- `playwright-report/`

## Commit Strategy

1. Unit tests for parseId, rate limiter, route params
2. Playwright setup (install, config, seed, global-setup)
3. Playwright E2E test files
