A brief overview of basic REST Assured usage and testing.

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What is REST API?

• An API is an Application Programming Interface.
• REST is acronym for REpresentational State Transfer.
• REST determines what the API looks like.

What is REST Assured?

💡 A tool that aims to bring simplicity for testing and validating the response of REST services in Java.

• Runs on top of existing unit testing frameworks like JUnit or TestNG
• Can be used to test XML as well as JSON based web services.
• Provides support for all known HTTP methods.
• Supports Gherkin syntax

Test Setup

In your IDE, create a new Maven project.

Dependencies in pom.xml

From Maven Repository, copy the latest stable versions of the following:

• TestNG or JUnit
• REST Assured
• Hamcrest

Paste them into your pom.xml file and refresh.

Creating the Test

In the newly created project folder, create a new class under /src/test/java.

Static Imports

In order to use REST assured effectively it's recommended to statically import methods from the following classes:

io.restassured.RestAssured.*
io.restassured.matcher.RestAssuredMatchers.*
org.hamcrest.Matchers.*

Gherkin Syntax Used In REST Assured

• Given() - 'Given' keyword, lets you set a background, here, you pass the request headers, query and path param, body, cookies. This is optional if these items are not needed in the request
• When() - 'when' keyword marks the premise of your scenario. For example, 'when' you get/post/put something, do something else.
• Method() - (get/post/put/delete)
• Then() - Your assert and matcher conditions go here

Common HTTP Methods

The verbs map to the CRUD operations.

• GET retrieves resources.
• POST submits new data to the server.
• PUT updates existing data.
• DELETE removes data.

HTTP Status Codes and Error Messages

• (100–199) Informational responses
• (200–299) Successful responses
• (300–399) Redirects
• (400–499) Client errors
• (500–599) Server errors

Very Simple GET Test

In this most basic test, I

• used GET to go to the website
• and asserted that statusCode is 200

If for whatever reason, it fails, then there is no need to look at any other test for this URL until this is fixed.

Simple POST Test

• Utilized JSONObjects to turn the inputted data into properly formatted JSON
• Output the newly formatted JSON to the console
• POST the data to the server
• Assert that the status code is 201

• and view the logs

Parameterization

• used in repeating the same test with different sets of data
• @DataProvider from TestNG is an easy way to feed test data to the actual tests

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If you want to learn more about REST Assured, take a look at the REST Assured usage guide on GitHub.

-- KaylaGilbert - 29 Jun 2020