encore-testing

SKILL.md

Testing Encore.ts Applications

Instructions

Encore.ts uses standard TypeScript testing tools. The recommended setup is Vitest.

Setup Vitest

npm install -D vitest

Add to package.json:
{
  "scripts": {
    "test": "vitest"
  }
}

Test an API Endpoint

// api.test.ts
import { describe, it, expect } from "vitest";
import { hello } from "./api";

describe("hello endpoint", () => {
  it("returns a greeting", async () => {
    const response = await hello();
    expect(response.message).toBe("Hello, World!");
  });
});

Run Tests

# Run with Encore (recommended - sets up infrastructure)
encore test

# Or run directly with npm
npm test

Using encore test is recommended because it:

Sets up test databases automatically

Provides isolated infrastructure per test

Handles service dependencies

Test with Request Parameters

// api.test.ts
import { describe, it, expect } from "vitest";
import { getUser } from "./api";

describe("getUser endpoint", () => {
  it("returns the user by ID", async () => {
    const user = await getUser({ id: "123" });
    expect(user.id).toBe("123");
    expect(user.name).toBeDefined();
  });
});

Test Database Operations

Encore provides isolated test databases:

// user.test.ts
import { describe, it, expect, beforeEach } from "vitest";
import { createUser, getUser, db } from "./user";

describe("user operations", () => {
  beforeEach(async () => {
    // Clean up before each test
    await db.exec`DELETE FROM users`;
  });

  it("creates and retrieves a user", async () => {
    const created = await createUser({ email: "test@example.com", name: "Test" });
    const retrieved = await getUser({ id: created.id });
    
    expect(retrieved.email).toBe("test@example.com");
  });
});

Test Service-to-Service Calls

// order.test.ts
import { describe, it, expect } from "vitest";
import { createOrder } from "./order";

describe("order service", () => {
  it("creates an order and notifies user service", async () => {
    // Service calls work normally in tests
    const order = await createOrder({
      userId: "user-123",
      items: [{ productId: "prod-1", quantity: 2 }],
    });
    
    expect(order.id).toBeDefined();
    expect(order.status).toBe("pending");
  });
});

Test Error Cases

import { describe, it, expect } from "vitest";
import { getUser } from "./api";
import { APIError } from "encore.dev/api";

describe("error handling", () => {
  it("throws NotFound for missing user", async () => {
    await expect(getUser({ id: "nonexistent" }))
      .rejects
      .toThrow("user not found");
  });

  it("throws with correct error code", async () => {
    try {
      await getUser({ id: "nonexistent" });
    } catch (error) {
      expect(error).toBeInstanceOf(APIError);
      expect((error as APIError).code).toBe("not_found");
    }
  });
});

Test Pub/Sub

// notifications.test.ts
import { describe, it, expect, vi } from "vitest";
import { orderCreated } from "./events";

describe("pub/sub", () => {
  it("publishes order created event", async () => {
    const messageId = await orderCreated.publish({
      orderId: "order-123",
      userId: "user-456",
      total: 9999,
    });
    
    expect(messageId).toBeDefined();
  });
});

Test Cron Jobs

Test the underlying function, not the cron schedule:

// cleanup.test.ts
import { describe, it, expect } from "vitest";
import { cleanupExpiredSessions } from "./cleanup";

describe("cleanup job", () => {
  it("removes expired sessions", async () => {
    // Create some expired sessions first
    await createExpiredSession();
    
    // Call the endpoint directly
    await cleanupExpiredSessions();
    
    // Verify cleanup happened
    const remaining = await countSessions();
    expect(remaining).toBe(0);
  });
});

Mocking External Services

import { describe, it, expect, vi, beforeEach } from "vitest";
import { sendWelcomeEmail } from "./email";

// Mock external API
vi.mock("./external-email-client", () => ({
  send: vi.fn().mockResolvedValue({ success: true }),
}));

describe("email service", () => {
  it("sends welcome email", async () => {
    const result = await sendWelcomeEmail({ userId: "123" });
    expect(result.sent).toBe(true);
  });
});

Test Configuration

Create vite.config.ts (required for ~encore imports):

/// <reference types="vitest" />
import { defineConfig } from "vite";
import path from "path";

export default defineConfig({
  resolve: {
    alias: {
      "~encore": path.resolve(__dirname, "./encore.gen"),
    },
  },
  test: {
    globals: true,
    environment: "node",
    include: ["**/*.test.ts"],
    coverage: {
      reporter: ["text", "json", "html"],
    },
  },
});

VS Code Integration

Install the Vitest extension and add to .vscode/settings.json:

{
  "vitest.commandLine": "encore test"
}

Note: For VS Code test explorer, disable file-level parallelism to avoid port conflicts:

// vite.config.ts
export default defineConfig({
  // ...
  test: {
    fileParallelism: false,  // Disable for VS Code
    // ...
  },
});

Re-enable for CI: encore test --fileParallelism=true

Guidelines

Use encore test to run tests with infrastructure setup

Each test file gets an isolated database transaction (rolled back after)

Test API endpoints by calling them directly as functions

Service-to-service calls work normally in tests

Mock external dependencies (third-party APIs, email services, etc.)

Don't mock Encore infrastructure (databases, Pub/Sub) - use the real thing