feat: Conver .http load tests to k6.io .js test files

[deicon]

Description:
This PR introduces a new feature: the ability to convert .http files into Grafana k6 scripts. This enables users to leverage existing .http files for load testing with k6.

Motivation:
Many developers already use .http files to define and test their APIs. Providing a conversion tool allows them to easily reuse these files for load testing with k6, reducing the effort required to set up performance tests.

What was changed:

• Added a new command-line flag -convert to main.go to trigger the conversion process.
• Created a new converter/k6 package with a Generate function that takes parsed .http requests and generates a k6 script.
• The Generate function handles placeholders, environment variables (from .env files), and request details to create a valid k6 script.
• Added a requireK6Generate helper function to isolate the k6 conversion logic and avoid unnecessary imports when not used.
• Added new files:
  • cmd/httprunner/convert_k6.go: Contains the requireK6Generate helper function.
  • converter/k6/generator.go: Contains the core logic for converting .http requests to k6 scripts.
  • converter/k6/generator_test.go: Contains unit tests for the k6 script generator.
  • docs/specs/k6-coverter.md: Contains documentation on the k6 converter.
  • examples/k6/loadtest.http: Example .http file to be converted to K6 format.

Tests:
New unit tests have been added in converter/k6/generator_test.go to verify the correct generation of k6 scripts, including placeholder handling, environment variable usage, and basic script structure.

[Copilot]

Pull Request Overview

This PR adds functionality to convert .http files into Grafana k6 load testing scripts, enabling developers to reuse existing HTTP request definitions for performance testing.

Key changes:

• Added a -convert k6 command-line flag to trigger conversion to k6 format
• Implemented a converter that preserves placeholders (converting {{.VAR}} to ${vars.VAR}), handles environment variables from .env files, and generates valid k6 JavaScript with proper options for iterations and delays
• Included comprehensive documentation and test coverage for the conversion feature

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
cmd/httprunner/main.go	Added -convert flag and conversion mode logic to handle k6 conversion requests
cmd/httprunner/convert_k6.go	Created helper function to isolate k6 converter imports
converter/k6/generator.go	Core conversion logic transforming HTTP requests to k6 JavaScript scripts
converter/k6/generator_test.go	Unit tests verifying placeholder conversion, environment variable handling, and script generation
docs/specs/k6-coverter.md	Documentation explaining conversion feature with examples
examples/k6/loadtest.http	Example HTTP file demonstrating conversion capabilities

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Corrected spelling of 'coverter' to 'converter' in filename.

[Copilot]

The variable respVar is assigned but never used. This appears to be dead code that should either be removed or utilized if it was intended for future functionality.