Add Backend Testing

Goal: Set up backend integration testing with Vitest using an isolated test database schema.

Task 1: Gather Information

Before starting, you need:

• service_id: The Timescale Cloud service ID for the database

If not provided, check the DATABASEURL in .env to find it, or use servicelist MCP tool.

Task 2: Set Up Test Infrastructure

1. Use the setup_testing MCP tool:

`` setuptesting(applicationdirectory: ".", serviceid: "<serviceid>") ``

1. Install Vitest:

``bash npm install -D vitest dotenv ``

1. Add test scripts to package.json:

``json { "scripts": { "test": "vitest run", "test:watch": "vitest" } } ``

1. Write integration tests for each tRPC router using this pattern:

```typescript import { describe, it, expect } from "vitest"; import { appRouter } from "~/server/api/root"; import { createCallerFactory } from "~/server/api/trpc"; import { db } from "~/server/db";

const createCaller = createCallerFactory(appRouter); const caller = createCaller({ session: null, db, headers: new Headers() });

describe("exampleRouter", () => { it("returns data", async () => { const result = await caller.example.getAll(); expect(result).toBeDefined(); }); }); ```

1. Run npm test and ensure all tests pass before completing

Task 3: Update CLAUDE.md

Add a Testing section to CLAUDE.md with the following content:

## Testing

This app uses Vitest for backend integration testing with an isolated test database schema.

**Test infrastructure:**
- Tests run against a separate PostgreSQL schema (see `DATABASE_SCHEMA` in `.env.test.local`)
- A dedicated test user has permissions only on the test schema
- Schema is automatically pushed before tests via global setup
- Tests use `.env.test.local` for database configuration (gitignored)

**Writing tests:**
\`\`\`typescript
import { describe, it, expect } from "vitest";
import { appRouter } from "~/server/api/root";
import { createCallerFactory } from "~/server/api/trpc";
import { db } from "~/server/db";

const createCaller = createCallerFactory(appRouter);
const caller = createCaller({ session: null, db, headers: new Headers() });

describe("myRouter", () => {
  it("returns data", async () => {
    const result = await caller.my.getData();
    expect(result).toBeDefined();
  });
});
\`\`\`

Also update:

• Add npm test and npm run test:watch to the Commands section
• Add "3. Add tests in src/test/routers" to the "New tRPC Router" checklist
• Update "Before Committing" section to include npm test:

``bash npm test && npm run check ``

Task 4: Commit

Ask the user if they want to commit the changes.

Task 5: Offer Further Hardening

Ask the user: "Would you like to add stricter TypeScript checks as well? This catches additional bugs that standard TypeScript misses."

If yes, follow the add-strict-checks skill.