• BFF = Consumer
• Auth Service = Provider
• Test verifies:
  • request body
  • response structure
  • role array
  • token fields

POST /auth/login - Request json

{
 "username": "john",
 "password": "secret"
}

RESPONSE json

{
  "accessToken": "jwt-string",
  "refreshToken": "jwt-refresh",
  "expiresIn": 900,
  "user": {
    "id": "u123",
    "email": "john@example.com",
    "displayName": "John Smith",
    "roles": ["ORDER.CREATE", "ORDER.VIEW"]
  }
}

Recommended Test Directory Structure

/tests
 ┣ unit
 ┃ ┣ api
 ┃ ┣ domain
 ┃ ┗ infrastructure
 ┣ integration
 ┃ ┣ api
 ┃ ┗ data
 ┗ pact
   ┣ consumers
   ┃ ┗ auth
   ┃   ┗ login.pact.test.ts
   ┣ providers
   ┃ ┗ auth
   ┃   ┗ verify-login.pact.test.ts
   ┗ helpers
      ┗ pact-setup.ts

Clean separation

Login Pact test lives in:

/tests/pact/consumers/auth/login.pact.test.ts

Helper Setup File

pact/helpers/pact-setup.ts

Create pact ts

import path from "path";
import { PactV3 } from "@pact-foundation/pact";

export function createPact(providerName: string) {
  return new PactV3({
    consumer: "BFF-Service",
    provider: providerName,
    dir: path.resolve(process.cwd(), "pacts"),
    logLevel: "INFO"
  });
}

login.pact.test.ts ts

import { createPact } from "../../helpers/pact-setup";
import { MatchersV3 } from "@pact-foundation/pact";
import axios from "axios";

const { like, eachLike } = MatchersV3;

describe("Login Contract", () => {

  const provider = createPact("Auth-Service");

  it("logs in successfully", async () => {

    provider
      .given("A valid user exists")
      .uponReceiving("Login request")
      .withRequest({
        method: "POST",
        path: "/auth/login",
        body: { username: "john", password: "secret" }
      })
      .willRespondWith({
        status: 200,
        body: {
          accessToken: like("token"),
          refreshToken: like("refresh"),
          user: {
            id: like("u123"),
            roles: eachLike("ORDER.CREATE")
          }
        }
      });

    await provider.executeTest(async mockServer => {
      const res = await axios.post(
        `${mockServer.url}/auth/login`,
        { username: "john", password: "secret" }
      );
      expect(res.status).toBe(200);
    });
  });
});

Pacts output to:

/pacts
 ┗ BFF-Service-Auth-Service.json