Skip to main content

(Micro) Service Testing with Postman - Newman - Docker

Image
By
Postman seems to become a defacto tool for service testing because the Postman is very user-friendly, easy-to-learn, all-in-one, lightweight and collaborating tool. Postman has been used for a long time but recently it has growing popularity because of a stable native application, collaboration feature after version 6.2, sharing of collections for team, interactive working with the team, mocks for isolated testing, environments for running the test for different test environments such as local, development, stage ... and many more features. For me, one of the biggest features is easy-to-use for everyone in a team so everyone in a team can use and update a postman collection easily. In this post, I want to explain how postman can be used efficiently.

Testing a Service and Writing Tests

With postman testing service is simple. Postman supports many methods like POST, GET, PUT, PATCH. Just select the correct method and hit the service URL you want to test. Postman also has everything that you need for complex requests headers, body, and parameters list. If you need something to prepare before sending the test request you can do it in the 'Pre-request Script'. If you need authorization you can add it 'Authorization' part which is an alternative to adding 'Authorization' parameter in the 'Header' section. If you want to check the not only the status code but also returning data you can add some assertions in the 'Tests' section. Postman supports Chai Assertion Library as BDD you can add self-descriptive assertion functions to your tests.


For complex scenario, you can write some javascript in the tab to simulate real behavior of your users. In the following scenario, a basic payment process is started with a post request and then the status of the request becomes `processing` but after that client needs to check the backend for each second until the status of the process become `completed`. For this scenario, in the `payment/payment-processing` request, until the status of this request is `processing` it calls itself recursively. If the status is not `processing` then it calls the next requests with another great feature of postman `setNextRequest` as  `postman.setNextRequest("payment/payment-complete")` see the example:

Pre-Request Script For Creating Data Dynamically

The pre-request script is designed to run something before the test so we can use it creating/updating/deleting test data for comprehensive test cases. In this section, you can use the embed node packages like `atob` and `btoa` for base encryption or `cheerio` is a form JQuery library to get value from a web object or `CriptoJs` cryptographic library to encrypt data with AES, DES or SHA. You can check the full list of embed libraries from postman document.

 In the following example, for RSA encryption with base64, I use an external web application. In the pre-requests tab of the request, `myData` is encrypted by sending a request to this web application. This is another important feature of the postman.

Running Postman Tests With Postman

You can run a collection with Postman collection runner easily by setting environment if necessary. Firs you can get my test collection which is written against to the blog project on GitHub. You can check the `service-test` section since it is a full project including every test that you need in your CI/CD. To run the tests, just click the play button next to the collection name, it opens the run panel then you click the `Run` button. See the following images:



Running Postman Tests With Newman

Newman is the CLI companion of postman so that you can run your tests with your environment by CLI. This is developed for integrating your test to CI/CD environment easily. In this example test data is created before the test run for a comprehensive test result. The full command is as follows:

You need node first, check this https://nodejs.org/en/download, then install the required packages, newman and newman-report-html:

npm install -g newman
npm install -g newman-reporter-html

to run with collection json:
newman run blog-sample-service.postman_collection.json \
 -e blog-local.postman_environment.json \
 --reporters cli,html \
 --reporter-html-template report-template.hbs

to run with collection url:
newman run https://www.getpostman.com/collections/ac3d0d9bbd8ae1bcfe5d \
 -e blog-local.postman_environment.json \
 --reporters cli,html \
 --reporter-html-template report-template.hbs


Running Postman Tests With Newman in Docker

For a better approach to run test on CI/CD pipeline is to use Docker so that we will not need to install any test related tools/languages/technologies to the client machine. This is becoming one of the industry standards. 

 Check the Dockerfile in the project. Basically, the base image is node installed Debian, we are installing the required node package which is newman and newman-reporter-html. Then we are running the test inside newman folder and the report will be created inside /newman folder. This Dockerfile gives us a newman entry point which can run it with newman commands. I have create Newman image in hub.docker, so we need to pull it first then we use it.
docker run \
 --network host \
 -v $PWD:/newman \
 gunesmes/newman-postman-html-report run https://www.getpostman.com/collections/ac3d0d9bbd8ae1bcfe5d  \
 -e blog-local.postman_environment.json \
 --reporters cli,html \
 --reporter-html-template report-template.hbs

We need to restore data during the test some data need to be ready. For each run, the database should be restored with the script provided in restore_database.sql. This file can be run by
bash restore_db.sh
bash run_service_test.sh



Get the  Postman Collection and the project.
Labels:Software testing

Popular posts for software testing and automation

Selenium Error "Element is not currently interactable and may not be manipulated"

By
Selenium webdriver can drive different browsers like as Firefox, Chrome or Internet Explorer. These browsers actually cover the majority of internet users, so testing these browsers possibly covers the 90% of the internet users. However, there is no guaranty that the same automation scripts can work without a failure on these three browsers. For this reason, automation code should be error-prone for the browsers you want to cover. The following error is caught when the test script run for Chrome and Internet Explorer, but surprisingly there is no error for the Firefox. Selenium gives an error like below: Traceback (most recent call last):   File "D:\workspace\sample_project\sample_run.py", line 10, in <module>     m.login()   File "D:\workspace\ sample_project \test_case_imps.py", line 335, in login     driver.find_element_by_id("id_username").clear()   File "C:\Python27\lib\site-packages\selenium-2.35.0-py2.7.egg\seleni...
Read more

Change Default Timeout and Wait Time of Capybara

By
One of the biggest challenge for automation is handling timeout problem. Most of the time, timeout is 60 seconds but it may sometimes not enough if you have badly designed asynchronous calls or the third party ajax calls. This makes handling timeout more complex. set large enough to tolerate network related problems. For Selenium based automation frameworks, like Capybara, default Webdriver timeout is set to Net::ReadTimeout (Net::ReadTimeout) Changing ReadTimeout If you have timeout problem for Capybara, it gives an error like above. This means that the page is not fully loaded in given timeout period. Even you can see that page is loaded correctly but webdriver wait until the Ajax calls finish. class BufferedIO #:nodoc: internal use only def initialize (io) @io = io @read_timeout = 60 @continue_timeout = nil @debug_output = nil @rbuf = '' end . . . . . def rbuf_fill beg...
Read more

Create an Alias for Interactive Console Work: Selenium and Capybara

By
If you are working on shell most of the time Aliases are very helpfull and time saving. For testing purposes you can use Alias for getting ready your test suites. In this post, I want to explain both running Selenium and Capybara on console and creating aliases for each.  This post is for Windows machines, if you are using Unix-like see   this post . Creating Scripts for Selenium and Capybara First of all, it is assumed that you have installed Selenium and Capybara correctly and they work on your machines. If you haven't installed, you can see my previous posts. I am using the Selenium with Python and the Capybara with Ruby. You can use several different language for Selenium but Capybara works only with Ruby.  Create scripts in a directory called scripts (in your home folder, like as  ~/scripts ) for your automation tool as following, save them as capybara.rb, sel.py :  Creating Aliases Depends on your favourite shell, you need to add the al...
Read more

Page-Object Pattern for Selenium Test Automation with Python

By
Page-object model is a pattern that you can apply it to develop efficient automation framework. With the page-model, it is possible to minimize maintenance cost. Basically page-object means that your every page is inherited from a base class which includes basic functionalities for every page. If you have some new functionalities that every page should have, you can simple add it to the base class. Base class is like the following: In this part we are creating pages which are inherited from base page. Every page has its own functionalities written as python functions. Some functions return to a new page, it means that these functions leave the current page and produce a new page. You should write as much as functions you need in the assertion part because this is the only part you can use the webdriver functions to interact with web pages . This part can be evaluate as providing data to assertion part.   The last part is related to...
Read more

Performance Testing on CI: Locust is running on Jenkins

By
For a successful Continuous Integration pipeline, there should be jobs for testing the performance of the application. It is necessary if the application is still performing well. Generally performance testing is thought as kinds of activities performed one step before going to live. In general approach it is true but don't forget to test your application's performance as soon as there is an testable software, such as an api end point, functions, and etc. For CI it is a good approach to testing performance after functional testing and just before the deployment of next stage. In this post, I want to share some info about Jenkins and Locust. In my previous post you can find some information about Locust and Jenkins. Jenkins operates the CI environment and Locust is a tool for performance testing. To run the Locust on Jenkins you need command line arguments which control the number of clients ,   hatch rate,  running locust without web interface and there s...
Read more