How To Use Newman In Postman

Leveraging Newman for Powerful Postman Collection Execution

Newman is a command-line tool designed to run Postman Collections, offering a flexible and efficient way to automate your API tests. This guide provides a comprehensive overview of how to use Newman with Postman, empowering you to streamline your testing workflow.

1. Installation:

Install Node.js: Newman relies on Node.js. Download and install the latest version from https://nodejs.org/.
Verify installation: Open your terminal and run node -v and npm -v. If you see the version numbers, you are good to go.
Install Newman: Use the npm package manager to install Newman:
Terminal window
```
npm install -g newman
```

2. Setting Up Your Postman Collection:

Create a Collection: In Postman, create a new collection to house your API test requests. Organize requests into folders for better structure.
Define Variables: Use variables to store dynamic values like URLs, API keys, and test data.
Write Assertions: Add assertions to each request to validate expected responses. Use Postman’s built-in assertion library or write custom scripts.
Save your Collection: Export the collection as a JSON file. You can find this option within the collection’s settings.

3. Running Newman from the Command Line:

Basic Execution: Run Newman with the following command, replacing collection.json with your collection file name:
Terminal window
```
newman run collection.json
```
Specify Environment: If your collection uses environment variables, refer to the environment file:
Terminal window
```
newman run collection.json -e environment.json
```

Reporting Options: Newman offers multiple reporting options:

JSON Output:

newman run collection.json -r json > results.json

HTML Report:

newman run collection.json -r html > report.html

CLI Output:
Terminal window
```
newman run collection.json -r cli
```

Iteration and Data:
- Sending Different Data: To send multiple requests with different data, use the -d flag and specify a JSON file containing your data.
  Terminal window
```
newman run collection.json -d data.json
```
- Repetition: Run the collection multiple times using the -n flag:
  Terminal window
```
newman run collection.json -n 10
```

4. Integrating Newman with CI/CD:

Using Jenkins/Travis CI: Configure your CI/CD pipeline to run Newman, ensuring your tests are automatically executed with every build.
Collecting Reports: Store Newman reports in artifacts, enabling analysis of test results and trend identification.

5. Example with Sample Code:

Collection (collection.json):

[
  {
    "info": {
      "_postman_id": "e2429ef3-678c-4c0f-849d-bdcd37f5d142",
      "name": "Weather API Tests",
      "schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json"
    },
    "item": [
      {
        "name": "Get Current Weather",
        "request": {
          "method": "GET",
          "header": [
            {
              "key": "Content-Type",
              "value": "application/json"
            }
          ],
          "url": {
            "raw": "{{weatherApiUrl}}/weather?q={{city}}&appid={{apiKey}}",
            "host": [
              "{{weatherApiUrl}}"
            ],
            "path": [
              "weather"
            ],
            "query": [
              {
                "key": "q",
                "value": "{{city}}"
              },
              {
                "key": "appid",
                "value": "{{apiKey}}"
              }
            ]
          },
          "description": "Fetches current weather data for a given city."
        },
        "response": []
      }
    ]
  },
  {
    "info": {
      "_postman_id": "5e671e90-d35b-448c-bf08-9c2d1ab8ba3c",
      "name": "Variables",
      "schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json",
      "variables": [
        {
          "id": "c173b482-1b22-4585-925f-4df031b905f3",
          "key": "weatherApiUrl",
          "value": "http://api.openweathermap.org/data/2.5"
        },
        {
          "id": "17020561-357c-4c15-ad45-7d287482e7c7",
          "key": "apiKey",
          "value": "YOUR_API_KEY" // Replace with your actual key
        }
      ]
    }
  }
]

Environment (environment.json):

[
  {
    "id": "838312e7-89cd-4c23-b89c-2fa461735401",
    "key": "city",
    "value": "London",
    "type": "string",
    "enabled": true
  }
]

Newman Execution Command:

newman run collection.json -e environment.json -r html > weather_report.html

This command runs the collection.json with the environment.json to fetch weather data for London and generates an HTML report named weather_report.html.

Conclusion:

By utilizing Newman in conjunction with Postman, you gain a robust solution for API testing automation. Newman’s command-line interface allows for seamless integration with your workflow, CI/CD pipelines, and code repositories. Leveraging its robust capabilities and reporting features empowers you to ensure the quality and reliability of your APIs.