# Tests - Annas RechnungsManager

Vitest-basiertes Test-Framework für kritische Geschäftslogik.

## Setup

```bash
# Install dependencies (already done)
npm install

# Run tests
npm run test           # Single run
npm run test:watch     # Watch mode
npm run test:ui        # Browser UI
npm run test:coverage  # With coverage report
```

## Test Structure

```
tests/
├── lib/
│   ├── tax.test.ts          # Steuerberechnungen (§14 UStG)
│   └── schemas.test.ts      # Zod-Validierung (Input-Sicherheit)
└── README.md
```

## Coverage

- ✅ **tax.ts** - German tax calculations (19%, 7%, Kleinunternehmer)
- ✅ **schemas.ts** - Input validation (Zod schemas)
- ⚠️ **invoice-number.server.ts** - Requires Prisma mocking (TODO)

## Critical Test Areas

1. **Tax Calculations** - Must be correct per German tax law
2. **Input Validation** - Prevent invalid data in DB
3. **Invoice Logic** - §14 UStG compliance
4. **Buchhaltung** - Double-entry bookkeeping accuracy

## Running Specific Tests

```bash
# Run only tax tests
npx vitest run tests/lib/tax.test.ts

# Run with coverage
npm run test:coverage
# Opens: ./coverage/index.html
```

## Writing New Tests

```typescript
import { describe, it, expect } from "vitest";
import { myFunction } from "@/lib/my-module";

describe("myModule", () => {
  it("should do something", () => {
    expect(myFunction()).toBe(expected);
  });
});
```

## CI Integration

Tests laufen automatisch in der Gitea Actions Pipeline (`.gitea/workflows/build.yml`).