API testing is an indispensable practice for ensuring the robustness and reliability of modern web systems and applications. It involves systematically dispatching various HTTP requests—such as GET, POST, PUT, and DELETE—to specific API endpoints. The primary goal is to validate how the server responds and to confirm the accuracy and integrity of the data exchanged.

At the heart of every effective API test lies a fundamental action: “When I send a METHOD request to ‘endpoint’.” This crucial step defines the precise moment an HTTP request is initiated. It instructs the testing framework to perform an action using a chosen HTTP method (like GET for retrieving data, POST for creating, PUT for updating, or DELETE for removing) directed at a specified API path. This action leverages any pre-configured data, headers, or base URLs set in preceding test steps.

Let’s look at some practical examples:

• When I send a GET request to "/users": This command retrieves a list of users.
• When I send a POST request to "/posts": This sends data to create a new post.
• When I send a PUT request to "/users/1": This updates the information for the user with ID 1.
• When I send a DELETE request to "/posts/1": This removes the post with ID 1.

A Real-World Scenario: Testing a Drupal CMS Blog Endpoint

Consider a scenario where we need to verify the /node/blog endpoint in a Drupal CMS. Our objective is to ensure that a GET request to this endpoint successfully returns a status code of 200, indicating a successful response.

Here’s how such a test might be structured using a Gherkin-like syntax:

Feature: API Functional Testing for Drupal CMS Blog Endpoint
  This feature demonstrates how to test the API endpoint for blog content.
  It focuses on sending a GET request to the blog node and checking the response status.

  Background:
    Given the API base URL is "http://localhost/test/drupalCMS/web/api/v1"

  Scenario: Check the blog node API response
    Given I am on "/api/v1"
     When I send a GET request to "/node/blog"
    Given I am on "/api/v1/node/blog"
     Then the API response code should be 200

In this example, the When I send a GET request to "/node/blog" line is the actionable command that performs the actual API call, leading to the verification of the response status code.

Automated API testing offers significant advantages, including considerable time savings and the prevention of human errors. By catching issues early in the development cycle, automated tests ensure that potential problems are identified and resolved long before they impact the end-user experience. While the process is serious, there’s a certain satisfaction in seeing tests pass, and even a valuable lesson to be learned when they highlight areas needing improvement.