Fix test_git_diff to use dynamic branch name

[joaommartins]

Description

Change test_git_diff to retrieve local default branch and using that as the checked-against branch name.

Publishing Your Server

Note: We are no longer accepting PRs to add servers to the README. Instead, please publish your server to the MCP Server Registry to make it discoverable to the MCP ecosystem.

To publish your server, follow the quickstart guide. You can browse published servers at https://registry.modelcontextprotocol.io/.

Server Details

• Server: git
• Changes to: tests

Motivation and Context

When running tests locally, if the configured default branch name is anything other than master, such as the now common main, the test_git_diff will fail.

How Has This Been Tested?

Local pytest ran and passed successfully.

Breaking Changes

No.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

[koic]

Thanks!