Testing RESTful web services with REST Assured

Test the RESTTesting RESTful web services using REST Assured

An open source workshop by …

Originally created by Bas Dijkstra – [email protected] – http://www.testautomation.com - @_basdijkstra

What are we going to do?

_RESTful web services

_REST Assured

_Get your hands dirty

Preparation

_Install Eclipse (or any other IDE)

_Install TestNG plugin (for Eclipse)

_Install m2e (or similar for any other IDE)

_Import Maven project into IDE

_Update project (Eclipse) or similar

What are RESTful web services?

_HTTP request methods (GET, POST, PUT, …)

_URI’s

_CRUD operations on dataPOST CreateGET ReadPUT UpdateDELETE Delete

An example

_GET http://api.zippopotam.us/us/90210

_Result:

Usage of RESTful web services

_Mobile applications

_Internet of Things

_API Economy

Why REST (and not SOAP, for example)?_Support for a multitude of data formats

_JSON_XML_…

_Smaller overhead and therefore better performance

Why SOAP(and not REST, for example)?_WS-Security

_WS-ReliableMessaging

_WS-AtomicTransaction

_Mostly used to secure banking applications

Tools for testing RESTful web services_Browser (using plugins like Postman for Chrome)

_Open source (SoapUI, REST Assured)

_COTS (Parasoft SOAtest, SoapUI Pro)

REST Assured

_Java library for writing tests for RESTful web services

_Removes a lot of boilerplate code

_Integrates seamlessly with existing Java-based testing frameworks_JUnit, TestNG_Selenium WebDriver

Configuring REST Assured

_Download from http://rest-assured.io

_Add as a dependency to your project

_Maven

REST Assured documentation

_Usage guide_https://github.com/rest-assured/rest-assured/wiki/Usage

_Links to other documentation (JavaDoc, getting started, release notes)_http://rest-assured.io/

A sample test

REST Assured features

_Support for HTTP methods (GET, POST, PUT, …)_Support for BDD / Gherkin (Given/When/Then)_Use of Hamcrest matchers for checks (equalTo)_Use of GPath for selecting elements from JSON response

About Hamcrest matchers

_Express expectations in natural language

_Examples:

_ http://hamcrest.org/JavaHamcrest/javadoc/1.3/org/hamcrest/Matchers.html

equalTo(X) Does the object equal X?

hasItem(“Rome”) Does the collection contain an item “Rome”?

hasSize(3) Does the size of the collection equal 3?

not(equalTo(X)) Inverts matcher equalTo()

About GPath

_GPath is a path expression language integrated into Groovy _REST Assured is built in Groovy

_Similar aims and scope as XPath for XML

_Documentation and examples:_http://groovy-lang.org/processing-xml.html#_gpath_http://groovy.jmiguel.eu/groovy.codehaus.org/GPath.html

GPath example

http://goessner.net/articles/JsonPath/

Validating technical response data_HTTP status code

_MIME-type of received responses

_Cookies and their value

_…

Our application under test

_Ergast F1 API

_Presents historical data of Formula 1 races, drivers, circuits, etc.

_Data can be returned in JSON and XML format

_API documentation at http://ergast.com/mrd/

Some examples

_Data for driver Max Verstappen (in JSON):

http://ergast.com/api/f1/drivers/max_verstappen.json

_A list of circuits for the 2015 season (in JSON):

http://ergast.com/api/f1/2015/circuits.json

Demo_ API documentation

_ How to use the test suite_ Executing your tests_ Reviewing test results

Get your hands dirty!

_RestAssuredExercises1

_Simple checks_Validating individual elements_Validating collections and items therein_Validating technical response properties

_RestAssuredExamples contains all examples from the presentation

Parameters in RESTful web services_Path parameters

_http://ergast.com/api/f1/drivers/max_verstappen.json_http://ergast.com/api/f1/drivers/hamilton.json

_Query string parameters_http://md5.jsontest.com/?text=testcaseOne_http://md5.jsontest.com/?text=testcaseTwo

_There is no official standard!

Using parameters in REST Assured

_Examples for query parameters:_ Call to http://md5.jsontest.com/?text=testcaseOne

_ Call to http://api.openweathermap.org/data/2.5/weather/?q=Kopenhagen&mode=xml

Using parameters in REST Assured

_Examples for path parameters:_ Call to http://ergast.com/api/f1/drivers/max_verstappen.json

_ Call to http://ergast.com/api/f1/drivers/alonso/constructors/renault/seasons.json

Using parameters in REST Assured

_Iterating over a collection of parameter values:

_ Creating pairs of driver ID’s and numbers:

_ Using test data in API calls and validation of response data:

Get your hands dirty!

_RestAssuredExercises2

_Data driven tests_Creating a test data object_Using test data in calling the right URI_Using test data in assertions

_RestAssuredExamples contains all examples from the presentation

Authentication

_Securing web services

_Basic authentication (preemptive / challenged)

_OAuth(2)

_Digest / Form

Basic authentication

_Username/password sent in header for every request

OAuth(2)

_Request of authentication token based on username and password (Basic authentication)

_Include authentication token in header of all subsequent requests

Measuring response times

_Measuring response times for individual requests

_Setting response time thresholds_Test fails when threshold is exceeded

_No full-fledged performance test

_First rough indication of API performance

Measuring response times

_An example:

Get your hands dirty!_RestAssuredExercises3

_Communicating with an OAuth2-secured API_ Requesting authentication token_ Using authentication token in subsequent requests

_Measuring API response times_ Execute a specific API call_ Evaluate response time against predefined threshold

_RestAssuredExamples contains all examples from the presentation

Sharing variables between tests

_Example: authentication tests

_Copy / paste required for OAuth2 token

_Preferably: store and retrieve for reuse!

Sharing variables between tests

_REST Assuredsupports thiswith extract()

Get your hands dirty!

_RestAssuredExercises4

_Try it for yourself

_Can you apply this to the Formula 1 API?

_RestAssuredExamplesParameterPassing contains all examples from the presentation

Executing tests in CI

_REST Assured-tests are no different from other Java (unit) tests

_Can be easily added to your CI/CD pipeline

_Part of the build process

_Demonstration (using Jenkins)

Questions

?

Contact

_Email: [email protected]

_Weblog: http://www.ontestautomation.com

_Twitter: @_basdijkstra