feat: support log_metric

[hfudev]

No description provided.

[Copilot]

Pull Request Overview

This PR adds a new log_metric fixture that allows users to record performance metrics or numerical data during tests in the Prometheus/OpenMetrics text-based format.

Key changes:

• New --metric-path CLI option to specify the output file for metrics
• New log_metric fixture that writes metrics in OpenMetrics format with labels
• Comprehensive test coverage for both with and without metric path scenarios

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
pytest-embedded/pytest_embedded/plugin.py	Adds --metric-path CLI option and implements metric_path and log_metric fixtures with file locking for thread-safe writes
pytest-embedded/tests/test_base.py	Adds test coverage for log_metric functionality with and without metric path
docs/usages/help_functions.rst	New documentation file explaining the usage and format of the log_metric fixture

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[Copilot]

The condition elif os.path.dirname(metric_path) will be False for paths in the current directory (e.g., 'metrics.txt'), which causes the directory creation to be skipped. This logic should handle the case where the file path is relative and has a non-empty directory component. Consider checking if os.path.dirname(metric_path) is not empty and that directory does not already exist, or use a simpler approach like unconditionally creating the directory if it's not empty.

Suggested change

	elif os.path.dirname(metric_path):
	os.makedirs(os.path.dirname(metric_path), exist_ok=True)
	else:
	dir_name = os.path.dirname(metric_path)
	if dir_name:
	os.makedirs(dir_name, exist_ok=True)