SimpleFinanceDash/.planning/codebase/TESTING.md

Testing

Current State

No tests exist yet. The codebase has zero test files — no Go tests, no frontend component tests, no E2E tests. CLAUDE.md references test commands but the infrastructure is not set up.

Planned Frameworks (from CLAUDE.md)

Backend (Go)

• Framework: Go standard library testing package
• Command: cd backend && go test ./...
• Package-level: cd backend && go test ./internal/api/...
• No test files exist (*_test.go)

Frontend

• Unit/Component Testing: Vitest
  • Command: cd frontend && bun vitest
  • Not yet installed (missing from package.json devDependencies)
• E2E Testing: Playwright
  • Command: cd frontend && bun playwright test
  • Not yet installed

Dependencies Needed

Frontend (not yet in package.json)

{
  "devDependencies": {
    "vitest": "^x.x.x",
    "@testing-library/react": "^x.x.x",
    "@testing-library/jest-dom": "^x.x.x",
    "@playwright/test": "^x.x.x"
  }
}

Backend

No additional dependencies needed — Go's testing package is built-in.

Configuration Files Needed

File	Purpose
frontend/vitest.config.ts	Vitest configuration
frontend/src/setupTests.ts	Test environment setup
frontend/playwright.config.ts	E2E test configuration

Recommended Test Structure

Backend

backend/
  internal/
    api/
      handlers_test.go     # Handler tests (HTTP request/response)
      router_test.go        # Route registration tests
    auth/
      auth_test.go          # JWT and bcrypt tests
    db/
      queries_test.go       # Database query tests (integration)

Frontend

frontend/
  src/
    components/
      BudgetSetup.test.tsx
      BillsTracker.test.tsx
      ...
    pages/
      DashboardPage.test.tsx
      LoginPage.test.tsx
      ...
    hooks/
      useAuth.test.ts
      useBudgets.test.ts
    lib/
      api.test.ts
      format.test.ts
  e2e/
    auth.spec.ts
    budget.spec.ts

Testing Patterns (Inferred from Architecture)

Backend

• HTTP handler testing: Use net/http/httptest with Chi router
• Database testing: Integration tests against PostgreSQL (pgxpool can be mocked or use test DB)
• Auth testing: Test JWT generation/validation, bcrypt hashing
• Context-based: All handlers use context.Context for user ID propagation

Frontend

• Component testing: Vitest + React Testing Library
• Hook testing: renderHook from Testing Library
• API mocking: Mock fetch or use MSW for /api/* endpoints
• i18n in tests: Wrap components with i18next provider

Priority Test Areas

Backend (High Priority)

1. Auth flow (register, login, JWT validation, password hashing)
2. Category CRUD (user isolation)
3. Budget operations (carryover calculations, item copying)
4. Database query correctness
5. Middleware (auth required, CORS)

Frontend (High Priority)

1. Auth flow (login/register forms, state management)
2. Budget selection & display
3. Budget item CRUD
4. Currency formatting
5. i18n language switching
6. Form validation