Batch Execution in Postman - Notes By ShariqSP

Batch Execution in Postman

Understanding Batch Execution

Batch Execution in Postman allows users to run multiple API requests sequentially or concurrently, making it possible to automate testing and execution of a set of related requests. This feature is useful for testing entire workflows, running collections of API calls for regression testing, and automating test suites. By running requests in batches, teams can ensure consistent API performance, functionality, and data integrity in a repeatable manner.

Methods for Batch Execution in Postman

Postman provides several ways to set up and run batches of requests, whether for a single environment or across multiple environments. Here are the primary methods:

1. Using Collections

Postman Collections are groups of API requests organized within a single collection. To create a collection, follow these steps:

  1. Go to the Collections tab in Postman.
  2. Click on the New Collection button.
  3. Add individual requests to this collection by dragging them into the collection or creating new requests directly within it.

After setting up a collection, it can be executed in batch mode with either Collection Runner or Newman (Postman’s command-line tool). Collections also support folders, allowing users to organize requests hierarchically within a single collection.

2. Running Collections in the Postman Collection Runner

The Postman Collection Runner is a built-in feature that allows users to run entire collections or specific folders within a collection.

Steps to execute a collection in the Collection Runner:

  1. Click on the Runner button (in the top left corner of Postman).
  2. Select the collection you want to run from the sidebar.
  3. Configure the environment, data file (if applicable), and iteration count.
  4. Click Run to execute all requests in the selected collection.

The Collection Runner provides options to run collections in batches with varying configurations, such as iterations, environments, and even a data-driven approach using CSV or JSON files.

3. Running Collections with Newman

Newman is a command-line tool for running Postman collections. It enables batch execution of collections outside the Postman app, ideal for CI/CD pipelines and automated environments. To run a collection with Newman:

// Install Newman via npm
              npm install -g newman
              
              // Run a collection with Newman
              newman run <collection_url_or_path> -e <environment_url_or_path> -d <data_file>

Newman supports batch execution options like setting the environment, providing a data file, and configuring the number of iterations. This flexibility is especially beneficial for automated testing scenarios.

4. Using Pre-Request and Test Scripts for Batch Workflow Control

Within a Postman collection, users can add Pre-Request and Test Scripts to control the execution flow and setup conditions for batch executions.

Examples of using scripts in batch execution:

  • Chaining requests: By storing response data (like an authentication token) in Postman variables, subsequent requests can use this data, creating a chained workflow.
  • Conditional execution: Using scripts to check conditions and selectively skip requests or retry failed requests if certain criteria are met.

Advanced Batch Execution Techniques

Advanced options include:

  • Data-driven Testing: Upload CSV or JSON data files in the Collection Runner or Newman to iterate over multiple sets of data, making it easier to test scenarios and edge cases.
  • Retry Logic: Implement retry logic using test scripts for requests that might require retries upon failure.
  • Parallel Execution with Newman: Use --parallel options in Newman (using specific Newman plugins) to achieve parallel request execution.

Example: Batch Execution of a Collection with Data File

Here’s an example of how to run a batch of requests with data-driven testing in Postman:

// Command for running a collection with Newman and data file
              newman run <path_to_collection> -e <path_to_environment> -d <path_to_data_file> --iteration-data <data_file.json>

In this command:

  • <path_to_collection>: The path to your Postman collection.
  • <path_to_environment>: The environment file to use for this execution.
  • <data_file.json>: A JSON or CSV file with data for each iteration, enabling the same collection to run with different data inputs.

With this approach, Postman allows for flexible and powerful batch executions, simplifying complex workflows and improving testing efficiency.

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