Support for Custom Test Report Formats - Fix: #3641

[SmartDever02]

PR Title

Add plugin-based custom test report formats (JSON/XML) and report_format config

Summary

• Address : Feature Request: Support for Custom Test Report Formats #3641
• Adds a pluggable report formatting system for tox test results.
• Introduces report_format option (core/env) to select output format.
• Provides built-in json and xml (JUnit) formatters.
• Exposes plugin hook tox_register_report_formatter for custom formats.
• Keeps backward compatibility: defaults to JSON if unspecified.
• Reuses --result-json path; extension is adjusted to selected format.

Key Changes

• New hook: tox_register_report_formatter in tox.plugin.spec.
• Formatter infra: tox.report.formatter with registry.
• Built-ins: tox.report.formatters.json, tox.report.formatters.xml.
• Config: report_format added via tox.report.config plugin.
• Journal writing now uses selected formatter.
• Updated help text for --result-json.

Usage

• In tox.ini:

  [tox]
  report_format = xml  # or json

• CLI:
  • tox --result-json report produces report.xml or report.json based on report_format.

Plugin Extension

• Third-party plugins can register formatters via:
  • tox_register_report_formatter(register) and register.register(MyFormatter()).

Compatibility

• Defaults to JSON when not configured.
• No breaking changes to existing workflows.