POSTMAN

more than what meets the eye

- Ritesh Ranjan

What's the talk about

• Features overview in Postman
• Scripting in Postman
• Writing Test Cases for API 
• Writing Integration Test
• Pros and Cons
• Comparisons

Collections & Folders

• Easy way to group and share a collection of APIs
• Provides scripting features in a Collection / Folder.
• Collection can used to Run a API integration test.

{{Variables}}

• Helps you to keep your code DRY 

Scopes

• Global
• Collection
• Environment
• Local
• Data

// Set variables
pm.environment.set("url", "www.google.com")

pm.global.set("url", "www.google.com")

// Get variables
pm.variables.get("url")
pm.environment.get("url")
pm.global.get("url")

Environment and Global

- Set of key-value pairs

- Can be exported and Shared

Scripting

• Powerful runtime based on Node.js
• Can add dynamic behavior to requests and collections

JavaScript code to execute during 2 events in the flow​

                - Pre-request script 

                - Test script under the Tests tab

Postman Sandbox

•  JavaScript execution environment
• Code you write in the pre-request/test script section is executed in this sandbox.
• Supported libs:   here

Detailed Execution Order

Pre-request script

• Js Scripts executed before a Test is Run
• Can be added to a Collection, Folder or a Request
• Default Sandbox Runtime of Postman is Available

// Prefix 
var prefix = "mdl_heroku_";

// Clear global variables 
pm.globals.unset(prefix + "sessionToken");


// Set a random user name
pm.globals.set(prefix + "userName", "Perf_rit_" + prefix + Date.now() + "@hello.mileiq.com");

Test Script

• JavaScript code executed after the request is sent
• Access to the pm.response
• Can be added to Collection, Folder and Test

// example using pm.response.to.have
pm.test("response is ok", function () {
    pm.response.to.have.status(200);
});

Condition Flow

• postman.setNextRequest("request_name")

// Set the request to be executed next

pm.setNextRequest("request_name");


// Stop workflow execution

pm.setNextRequest(null);

Collection Run

• Groups of requests that can be run together as a series of requests
• Can be run against an environment
• Used to build integration test suites
• Can pass data between API requests
• Can have conditional flows
• Can also use CSV data file

DEMO

Pros

• Already most used API testing tool for devs
• Good way to publish sample request
• No need to learn new scripting
• Natural for most devs to write in JS
• Can be easly integrated with CI/CD using newman

newman run postman-config/MDL_Rest_Login_Flow_Automated.postman_collection.json 
        -e postman-config/Actual_Router_Perf.postman_environment.json 
        --exitCode 1

Comparisons

• Similar Desktop based Tools
  • SoapUI
  • Jmeter
  • Paw3
  • insomnia
  • stoplight
• Cloud based
  • assertible 
  • blazemeter

Cons

• Including custom js libraries sandbox is hacky.
• No easy way to call API of different collection.
• Custom script to connect to DB is difficult (hacky way)
• Cannot be used as Load testing
• Difficult to have Code Reviews and Pull Requests as collections are stored as JSON files.
• No Direct GIT integration like Soap UI

Questions