Forem: Jeffery (Kojo) Osei

Beginners guide to Writing Newman API Tests

Jeffery (Kojo) Osei — Fri, 04 Dec 2020 00:31:17 +0000

Hello there 🤓,

I trust you are well and keeping safe, today we will be doing a little JavaScript-ing with Postman's Newman tool! 😍.

So to start with, I just want to say, Newman is an awesome Postman command line tool. Newman basically helps you automate your Postman tests with ease.

In my previous post here, I explained in layman's terms how to write basic Postman tests for your APIs and today we will be running something similar using Newman but with a public Space-X Api which I have gone ahead to tweak for this test (added test cases to assert their responses).

Let's go! 🏃🏽‍♂️

REQUIREMENTS 📝

For windows users, open up Powershell
For Linux users, use this key combination to start your terminal Ctrl + Shift + T
For Mac users, Open the search prompt Command + Space (bar) and type terminal, press enter to open it up.

STEPS 🪜

Install NodeJS
Create Folder Structure
Install Postman's Newman
Run Newman Test
View Results

💻 Install NodeJS :

Installing NodeJS is pretty straight forward, visit their download page here, download your platform version to install. Kindly make sure its version 10 or higher.

After installing, head to your Terminal and enter the command below to check if everything is good to go.

node -v && npm -v

You should see an output like the one below:

📝 If your versions printed do not match the above, do not worry, you are good to go! 💪🏽.

📁 Create Folder Structure :

Before we can run our tests programmatically we need to setup our working directories, run the command below in your terminal to proceed.

mkdir newman-training && cd newman-training

This will create our working directory and change directory into it.

🤸‍♂️ Install Postman's Newman :

Now that we have our working directory setup, we need to install newman and a couple more NodeJS modules we need, use the command below.

npm install newman request rimraf newman-reporter-csv newman-reporter-html newman-reporter-htmlextra --save --force

If everything went well you should see an output similar to the one below:

💥 Run Newman Test :

Now that we have Newman installed and ready, lets start scripting, use the command below to create the file and edit using nano in your terminal.

nano postman.js

Now copy and paste the code snippet below in your terminal.

const fs = require("fs"); // require node file system
const rimraf = require("rimraf"); // require rm package
const request = require("request"); // require node js request
const newman = require("newman"); // require newman
const postman_collection_url =
  "https://raw.githubusercontent.com/clonne101/newman-training/main/space_x.json";
const postman_collection_name = "space_x.json";

// method responsible for obtaining our collection
function getCollectionFile(postman_collection_url, postman_collection_name) {
  return new Promise((resolve, reject) => {
    // check if postman collection json exist, if not download it
    fs.readFile("./" + postman_collection_name, function (err) {
      if (err) {
        // write to log
        console.log(
          postman_collection_name + " collection file not found, downloading..."
        );

        // get the file contents
        request(postman_collection_url, function (error, response, body) {
          if (!error && response.statusCode == 200) {
            // write to log
            console.log("Retrieved file successfully, saving...");

            // write to file
            fs.writeFile(postman_collection_name, body, function (fail) {
              if (fail) {
                console.log(fail);
                reject(fail);
              }

              // write to log
              console.log(postman_collection_name + " saved successfully!");
              resolve(true);
            });
          } else {
            console.log(err);
            reject(err);
          }
        });
      } else {
        // write to log
        console.log(postman_collection_name + " exist proceeding...");
        resolve(true);
      }
    });
  });
}

// promise declaration
const promises = [
  getCollectionFile(postman_collection_url, postman_collection_name),
];

// promise resolver
Promise.all(promises).then((result) => {
  if (result) {
    // add space
    console.log("\n");

    // remove reporter folder
    rimraf("./newman", function () {
      console.log("Old newman reporters removed successfully...");
    });

    // call newman.run to pass `options` object and wait for callback
    newman.run(
      {
        collection: require("./" + postman_collection_name),
        reporters: ["html", "csv", "json"],
      },
      function (err) {
        if (err) {
          throw err;
        }
        console.log("\nCollection run complete!\n");
      }
    );
  }
});

To save and close the file, use these keyboard combination Ctrl + x and then Y and lastly press your Enter key.

Lets quickly recap on what the file we just created contains, so we begin by requiring modules we need, we then went ahead to download our postman collection json file, saved it and then went ahead to run newman which upon completion outputs the results to .csv, .json and .html files into a newman folder for review.

Now to run the test, use the command below and you should get a response similar to the screenshot below.

node postman.js

🎉 View Results :

Now that we all done, lets go see how we did on our tests (Wheew! 😅). Head to your file explorer or finder if you are on a Mac. Navigate to your newman-training folder and in there you would find the newman folder which contains our results.

Double-click on the .html file and you should have a view like the one below show up in your default browser! 😍.

In the above screenshot we see all our test cases passed and further more summary for each of our request.

Awesome! 👏, now we are all done, I urge you to try out some more Newman examples in your free time, Postman offers Public APIs you can play with. Happy Newman Testing 😉.

🐱‍💻 Resources:

Kindly find below links to resources you can use as a guide and also links to my social media should you need to make contact for any challenges you might have or just to have a short conversation if you are starting out.

Postman: https://www.postman.com
Postman Public APIs: https://www.postman.com/explore
Postman Learning: https://learning.postman.com/docs/getting-started/introduction
Postman Newman: https://learning.postman.com/docs/running-collections/using-newman-cli/command-line-integration-with-newman/

GitHub repository for the test code:
https://github.com/clonne101/newman-training

Social Links:
Website: https://jefferyclonne.com
Twitter: https://twitter.com/@clonne101
LinkedIn: https://www.linkedin.com/in/jeffery-osei-551626a6

[Video] Postman API Testing

Jeffery (Kojo) Osei — Sun, 22 Nov 2020 13:50:43 +0000

Hello there 🤓, this is the video upload of an earlier post which can be found here.

🐱‍💻 Happy Testing!

Beginners guide to writing Postman API Tests

Jeffery (Kojo) Osei — Sun, 22 Nov 2020 12:48:12 +0000

Hello there 🤓, today I want to give you a gist on a tool I have been using both at work and in my personal projects for testing the APIs I write.

Postman, this to me is by far one of the best tools for running API tests and automation if needed, I have been on this tool for more than a year now.

In the beginning I used it as any other REST API client, just add in my requests and see a positive response come in but there was so much I could have achieved if only I knew this.

So today I would like you to join me on a short adventure of writing a simple API test with Postman, let's go!.

STEPS 🪜

Install Postman
Add Environment Variable
Add Test Request
Add Test Cases

💻 Install Postman :

Installing the Postman app is really easy, visit this page and obtain your platform version (Mac, Windows, Linux).

🍕 Add Environment Variable :

Environment variables in Postman aids you when setting up your request, a good example is setting your API url for re-use in other places. To do this, Open your installed Postman app and click on the Manage Environment button at the top right corner of the window as seen below.

You will be greeted with a popup window. At the bottom right corner, click on the Add button as seen below.

In the next view you will find a section to enter your environment name, set your variable name, add an initial value and lastly a current value, find an example below.

📝 To follow this test, you can set your initial value and current value to the URL below.

http://play.jefferyclonne.com/code/postman-training/index.php?limit=0

Initial value:
This is the value shared to your team or publicly when you decide to share your request with others.
Current value:
This is the value used when Postman is making requests using your environment, it is an ephemeral value that does not get saved, only exist locally.

Now Add and exit out of the window, check the Environments drop-down to make sure yours is selected, as seen below.

🧱 Add Test Request :

If you are using the test URL above, follow this setup. In your Postman window click on the + button as shown below.

Now in the address bar enter your environment variable {{url}} and click on the Send button to make sure the API is reachable, as seen below.

🎄 Add Test Cases :

Now that we have everything setup (wheew! 😅), lets start writing our test cases! 🤩.

In your Postman window select the Tests tab to get started as seen below.

Now lets write our cases:

1. Test status response is 200: In this test we try to check if the response from the API has a status of 200, meaning everything is OK.