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Rest API Testing Tutorials

REST API testing verifies RESTful APIs’ functionality, reliability, performance, and security that connect different software systems. It ensures that the API returns the expected responses for client requests.

Rest API

REST (Representational State Transfer) is an architectural style used for designing APIs that enable communication between client and server over HTTP. REST APIs are widely used in modern software applications due to their simplicity and scalability. REST API testing ensures that these APIs function correctly, return expected data, and handle errors gracefully.

REST API Testing Tutorials

What is REST API Testing?

REST API testing involves validating:

  • Functionality: Ensuring the API meets functional requirements.
  • Performance: Checking speed, reliability, and scalability.
  • Security: Ensuring secure data exchange.
  • Data Validation: Verifying input/output data formats and responses.

Concepts in REST API Testing

HTTP protocol is used in REST as it is a simple, widely adopted, and stateless protocol that is ideal for building web services. HTTP is Stateless meaning each HTTP request in REST is independent and contains all the necessary information, meaning no server-side session is required. This fits perfectly with REST’s stateless principle.

Why HTTP is preferred?

  • Stateless Communication: Each HTTP request in REST is independent and contains all the necessary information, meaning no server-side session is required. This fits perfectly with REST’s stateless principle.
  • Standardization: HTTP is a standard protocol that works across different systems and platforms, making it easy to implement RESTful services.
  • Scalability: HTTP can handle a large number of requests and responses, making it suitable for scalable web services.
  • Uniform Interface: HTTP methods (GET, POST, PUT, DELETE) directly map to REST operations, simplifying the design and usage of RESTful APIs.
  • Wide Support: Most web browsers, servers, and client applications natively support HTTP, ensuring interoperability across different devices and technologies.

HTTP Methods

GET: Retrieve data.
POST: Create new data.
PUT/PATCH: Update existing data.
DELETE: Remove data.
Endpoints: URL paths that identify the resources in the API.

Status Codes: Indicate the result of a request.

For example:

200: OK
201: Created
400: Bad Request
401: Unauthorized Request
404: Not Found
500: Internal Server Error

Headers: Include metadata, such as authentication tokens or content types.

Request Body: Contains data sent to the API, typically in JSON or XML format.

Response: contains the response for the API call from the server.

Tools for REST API Testing

  • Postman
  • RestAssured
  • SoapUI

Postman Tool

What is Postman?

Postman is a powerful, user-friendly tool widely used for testing REST APIs. It supports creating, managing, and automating API tests through an intuitive interface.

  • Download and Install: Visit Postman and download the app.
  • Create a Request: Choose HTTP methods (GET, POST, PUT, DELETE) and add the endpoint URL.
  • Add Parameters: Include query parameters, headers, and body for the request.
  • Send and View Responses: Send the request and view detailed responses, including status codes and JSON data.

 

RestAssured

A Java-based library for automating REST API tests. It allows writing comprehensive test scripts and integrates seamlessly with test frameworks like JUnit or TestNG.

SoapUI

A versatile tool supporting REST and SOAP APIs. It offers advanced testing capabilities, including security and performance testing.

Popular Automation Tools

Automation saves time, ensures consistency, and enables continuous testing in development pipelines.

  • RestAssured: A Java-based library designed for automating REST API testing with comprehensive features.
  • Karate: An all-in-one framework for API testing and performance testing with built-in DSL (Domain-Specific Language).
  • Postman Newman: A CLI tool for running Postman collections in automation pipelines.

Mantis Rest API

MantisBT (Mantis Bug Tracker) is an open-source issue-tracking system. Its REST API allows seamless integration and programmatic access to its functionalities.

REST API testing is crucial for validating communication between software systems. Beginners can start with tools like Postman to understand the basics and gradually move to automation tools for advanced testing.

Karate Tutorials