pactum

What is pactum?

Pactum is a REST API testing tool that allows you to write tests in a simple and readable manner. It supports various types of testing including functional, end-to-end, and performance testing. Pactum is designed to be easy to use and integrates well with other testing frameworks.

What are pactum's main functionalities?

API Testing

This feature allows you to test REST APIs by making HTTP requests and validating the responses. The code sample demonstrates a GET request to a sample API and checks the status code and JSON response.

const pactum = require('pactum');
pactum.spec()
  .get('https://jsonplaceholder.typicode.com/posts/1')
  .expectStatus(200)
  .expectJson({
    userId: 1,
    id: 1,
    title: 'sunt aut facere repellat provident occaecati excepturi optio reprehenderit',
    body: 'quia et suscipit\nsuscipit...'
  })
  .toss();

Mock Server

Pactum allows you to create a mock server to simulate API responses. This is useful for testing scenarios where the actual API is not available. The code sample shows how to set up a mock server that responds to a GET request.

const pactum = require('pactum');
const { mock } = pactum;
mock.addInteraction({
  request: {
    method: 'GET',
    path: '/api/users'
  },
  response: {
    status: 200,
    body: [{ id: 1, name: 'John Doe' }]
  }
});
mock.start(3000);

BDD Style Testing

Pactum supports Behavior-Driven Development (BDD) style testing, which makes tests more readable and easier to understand. The code sample demonstrates how to write BDD style tests using Given, When, and Then.

const pactum = require('pactum');
const { Given, When, Then } = require('pactum').bdd;
Given('a user exists', () => {
  pactum.spec()
    .get('https://jsonplaceholder.typicode.com/users/1')
    .expectStatus(200);
});
When('I get the user details', () => {
  pactum.spec()
    .get('https://jsonplaceholder.typicode.com/users/1');
});
Then('I should see the user details', () => {
  pactum.spec()
    .get('https://jsonplaceholder.typicode.com/users/1')
    .expectJson({
      id: 1,
      name: 'Leanne Graham'
    });
});

Other packages similar to pactum

supertest

Supertest is a popular library for testing Node.js HTTP servers. It provides a high-level abstraction for testing HTTP, making it easy to write tests for your APIs. Compared to Pactum, Supertest is more focused on testing Express.js applications and does not offer built-in support for BDD style testing or mock servers.

chai-http

Chai-HTTP is an extension of the Chai assertion library that provides HTTP integration testing capabilities. It allows you to make HTTP requests and assertions in a fluent style. While Chai-HTTP is powerful, it requires more setup and does not offer the same level of built-in features as Pactum, such as mock servers and BDD style testing.

nock

Nock is a library for HTTP mocking and expectations. It allows you to intercept HTTP requests and provide predefined responses, making it useful for testing without making actual network requests. Nock is more focused on mocking and does not provide the same level of API testing capabilities as Pactum.

README

pactum

pactum is a REST API Testing Tool that combines the implementation of consumer driven contract library Pact for JavaScript.

Documentation

• Pactum
• Component Testing
• Contract Testing
  • Consumer Testing
  • Provider Verification
• Interactions
• Mock Server

Installation

npm install --save-dev pactum

Usage

Component Testing

Running a single component test expectation.

const pactum = require('pactum');

it('should be a teapot', async () => {
  await pactum
    .get('http://httpbin.org/status/418')
    .expectStatus(418)
    .toss();
});

# mocha is a test framework
mocha /path/to/test

Learn more about pactum as a component tester here

Contract Testing

Contract Testing is a technique for testing interactions between applications (often called as services) that communicate with each other, to ensure the messages they send or receive conform to a shared understanding that is documented in a contract.

Learn more about contract testing at pact.io

Learn more about contract testing with pactum at Contract Testing

Contract Testing has two steps

1. Defining Consumer Expectations (Consumer Testing)
2. Verifying Expectations on Provider (Provider Verification)

Consumer Testing

Running a consumer test with the help of a mock server & a single pact interaction. If the pact interaction is not exercised, the test will fail.

const pactum = require('pactum');

before(async () => {
  await pactum.mock.start();
});

it('GET - one interaction', async () => {
  await pactum
    .addPactInteraction({
      provider: 'projects-service',
      state: 'when there is a project with id 1',
      uponReceiving: 'a request for project 1',
      withRequest: {
        method: 'GET',
        path: '/api/projects/1'
      },
      willRespondWith: {
        status: 200,
        headers: {
          'content-type': 'application/json'
        },
        body: {
          id: 1,
          name: 'fake'
        }
      }
    })
    .get('http://localhost:9393/api/projects/1')
    .expectStatus(200)
    .expectJsonLike({
      id: 1,
      name: 'fake'
    })
    .toss();
});

after(async () => {
  await pactum.mock.stop();
});

Learn more about pactum as a consumer tester at Consumer Testing

Provider Verification

Running a provider verification test with the help of a pact broker.

await pactum.provider.validate({
  pactBrokerUrl: 'http://pact-broker:9393',
  providerBaseUrl: 'http://user-service:3000',
  provider: 'user-service',
  providerVersion: '1.2.3'
});

Learn more about pactum as a provider verifier at Provider Verification

Mock Server

Running pactum as a standalone mock server.

const pactum = require('pactum');
pactum.mock.setDefaultPort(3000);
pactum.mock.start();

Learn more about pactum as a mock server here

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