# Testing Design
## Goal
Add unit and integration tests to catch regressions and verify critical paths before deploy.
## Framework
**Vitest** - Fast, native ESM support, Jest-compatible API.
## Test Structure
```
tests/
unit/
oauth/
helpers.test.ts # generateSecureToken, hashCodeVerifier
mcp/
handler.test.ts # validateAccessToken, handleMcpMethod
tools/
drive.test.ts # Tool handler logic
docs.test.ts
sheets.test.ts
integration/
oauth.test.ts # Full OAuth flow endpoints
mcp.test.ts # MCP JSON-RPC endpoints
mocks/
firestore.ts # Mock Firestore client
google-apis.ts # Mock Google Drive/Docs/Sheets APIs
secrets.ts # Mock Secret Manager
setup.ts # Global test setup
```
## Mocking Strategy
### Firestore
```typescript
export const mockFirestore = {
doc: vi.fn().mockReturnValue({
get: vi.fn(),
set: vi.fn(),
delete: vi.fn(),
}),
};
```
### Google APIs
```typescript
export const mockDrive = {
files: { list: vi.fn(), get: vi.fn(), create: vi.fn(), update: vi.fn() },
};
export const mockDocs = {
documents: { get: vi.fn(), batchUpdate: vi.fn() },
};
export const mockSheets = {
spreadsheets: { values: { update: vi.fn() } },
};
```
### Secret Manager
```typescript
export const mockSecrets = {
accessSecretVersion: vi.fn().mockResolvedValue([{
payload: { data: Buffer.from('fake-secret') }
}]),
};
```
## Critical Path Tests
### Unit Tests
| File | Tests |
|------|-------|
| `oauth/helpers` | `generateSecureToken` returns hex of correct length, `hashCodeVerifier` produces valid base64url |
| `mcp/handler` | `validateAccessToken` returns valid/invalid/expired correctly |
| `mcp/tools/*` | Each tool validates required args, returns proper ToolResult format |
### Integration Tests
| Endpoint | Tests |
|----------|-------|
| `GET /.well-known/oauth-authorization-server` | Returns correct OAuth metadata |
| `POST /register` | Creates client, returns credentials |
| `GET /authorize` | Validates params, redirects to Google |
| `POST /token` | Exchanges code for tokens, validates PKCE |
| `POST /` (MCP) | `initialize` returns capabilities, `tools/list` returns all 16 tools, `tools/call` executes tool |
## Configuration
### Dependencies
```json
{
"devDependencies": {
"vitest": "^2.0.0",
"@vitest/coverage-v8": "^2.0.0",
"supertest": "^7.0.0",
"@types/supertest": "^6.0.0"
}
}
```
### vitest.config.ts
```typescript
import { defineConfig } from 'vitest/config';
export default defineConfig({
test: {
globals: true,
environment: 'node',
setupFiles: ['./tests/setup.ts'],
coverage: {
provider: 'v8',
include: ['src/**/*.ts'],
exclude: ['src/index.ts'],
},
},
});
```
### package.json scripts
```json
{
"scripts": {
"test": "vitest run",
"test:watch": "vitest",
"test:coverage": "vitest run --coverage"
}
}
```
## Priority Order
1. MCP endpoint tests (core functionality)
2. Token endpoint (security-critical)
3. OAuth helpers (foundational)
4. Tool handlers (high value, many edge cases)
