Newman-Based API Test Runner with Input Iterations

A command-line utility that automates Postman collections using Newman. Ideal for CI/CD pipelines, tests or updates, it handles authentication, token generation, and data-driven execution via CSV files—complete with request/response logging and built-in delays to avoid race conditions.

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Table of Contents

#	Section
1	Newman CLI Overview
2	Key Features of Newman
3	Advantages Over Postman
4	Project Features
5	Prerequisites
6	Configuration
7	Script Overview (script.js)
8	Running the Script
9	Example Output
10	Next Steps
11	Conclusion
12	Support
13	References

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Newman CLI Overview

Newman is the headless command-line companion to Postman, built for automated API testing in CI/CD environments. It executes Postman collections without a GUI, supports multiple reporters, and can be integrated into any pipeline.

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Key Features of Newman

• Headless Execution: Invoke collections via CLI for non-interactive automation.
• CI/CD Integration: Works seamlessly with Jenkins, GitLab CI, CircleCI, Azure DevOps, and more.
• Custom Reporting: Output in CLI, HTML, JSON, or JUnit formats for easy consumption.
• Environment Support: Pass and export environment files to target dev, staging, or prod setups.
• Cross-Platform: Compatible with Windows, macOS, and Linux.

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Advantages Over Postman

• Automation Focus: Designed for scripted, repeatable runs; no manual clicks required.
• Deeper CI/CD Integration: Built-in support for pipeline hooks, exit codes, and parallel runs.
• Flexible Reporting: Choose your format and level of detail for integration with external dashboards.
• Dynamic Environments: Swap environment variables on the fly via CLI flags.
• Execution Control: Fine-grained options for iteration counts, delays, and concurrency.

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Project Features

• Authentication Collection: Generates an access token before each data run.
• Operational Collection: Processes CSV files iteratively, one row per request.
• Logging: Streams raw request bodies and validates JSON responses to the console.
• Delay Handling:
  • AUTH_DELAY_MS (default 10 000 ms) between auth and operational runs.
  • BATCH_DELAY_MS (default 20 000 ms) between different input files.

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Prerequisites

• Node.js (v14+ recommended)
• Newman installed globally:
  npm install -g newman
• Postman collections and environment JSON:
  • Authentication.postman_collection
  • OperationalCollection.postman_collection
  • Environment.postman_environment.json
• Optional CSV input files (each with header row + data rows)

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Configuration

1. Collections & Environment
   Place the following files in your project root:
   Authentication.postman_collection
OperationalCollection.postman_collection
Environment.postman_environment.json

2. Input Files

   • Ensure each CSV (e.g., input1.csv) has a header row followed by data rows.
   • Add the filenames to the inputFiles array at the top of script.js.

3. Adjustable Delays

   • Modify AUTH_DELAY_MS and BATCH_DELAY_MS constants in script.js if needed.

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Script Overview (script.js)

• runCollections(inputFile)

  • Runs the auth collection to refresh the token.
  • Waits AUTH_DELAY_MS.
  • Runs the operational collection with iterationData from the CSV.

• logRequestResponse(args, isResponse)

  • On each request: logs raw body.
  • On each response: attempts JSON parse, logs parsed object or raw text.

• getIterationCount(inputFile)

  • Reads CSV, counts rows minus header to determine iteration count.

• executeAllInputFiles()

  • Loops through inputFiles, calls runCollections for each.
  • Waits BATCH_DELAY_MS between runs.

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Running the Script

node script.js

Ensure you have the correct files in place and Newman installed.

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Example Output

Running AUTH_COLLECTION to generate token... ✔ AUTH_COLLECTION run complete. Waiting for 10 seconds before running the UPDATE_COLLECTION... Running UPDATE_COLLECTION with 5 iterations using input file: input1.csv → Request: {"username":"user1","action":"update"} ← Response: {"status":"success","id":12345} … Waiting for 20 seconds before next input file… All collections executed. Data saved.

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Next Steps

• Add new CSV files to inputFiles in script.js.
• Integrate node script.js into your CI/CD pipeline’s test stage.
• Extend logging to write to files or external logging services.
• Implement additional error-reporting (e.g., Slack notifications).

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Conclusion

Newman excels at automated, headless testing and CI/CD integration, while Postman’s GUI is better for manual API exploration. For teams aiming to embed API tests in a DevOps pipeline, Newman delivers greater flexibility and reliability.

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Support

For questions or issues, please open an issue in the project repository.

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References

• Official Newman Documentation