Test an API endpoint with Minitest

In Ruby is extremely important to test everything, why? Because it’s an interpreted language and is dynamically typed, so errors will pop up at runtime (it could be production ☠️).

Apart from code errors if we change the response of an endpoint it’s very probable that we will break the client apps. So remember! At least 1 test for each endpoint.

And why Minitest? It’s fast, simple and you already know Ruby 💎

Now imagine we have a simple endpoint at /api/v1/cars to return the cars available in our database. Let’s see how to do it with a simple integration test:

require 'test_helper'

class Api::V1::CarsTest < ActionDispatch::IntegrationTest
  test 'get a list of cars' do     
    get api_v1_cars_path

    assert_response :success  
    
    cars = JSON.parse(response.body).dig('cars')
      
    assert_equal cars.length, 3

    assert_equal 'Dacia', cars.first.dig('name')
  end
end

For the dummy data on your tests, you can use Rails fixtures or FactoryBot.