fix: update integration tests to work with modern Git default branch

[pawelma]

Git Hook Management Improvements

Overview

The git-pair tool has been enhanced with improved git hook management that preserves existing hooks while seamlessly integrating git-pair functionality.

Key Improvements

1. Hook Preservation

• Before: Completely overwrote existing prepare-commit-msg hooks
• After: Preserves existing hook content and only manages the git-pair section

2. Sectioned Management

• Uses clear markers (# BEGIN git-pair and # END git-pair) to delimit git-pair functionality
• Only modifies the git-pair section, leaving other hook logic intact
• Safe installation and removal without affecting existing workflows

3. Smart Hook Removal

• Selective removal: Only removes git-pair sections when clearing co-authors
• Complete removal: Removes entire hook file only if it contains only git-pair content
• Content preservation: Keeps existing hook logic when removing git-pair sections

Implementation Details

Hook Installation Process

1. Read existing hook: Checks if prepare-commit-msg already exists
2. Merge or append:
   • If git-pair section exists: replaces it with updated content
   • If no git-pair section: appends new section with proper markers
   • If no hook exists: creates new hook with shebang and git-pair section

Hook Removal Process

1. Locate git-pair section: Finds content between # BEGIN git-pair and # END git-pair
2. Remove section: Extracts only the git-pair portion
3. Clean up spacing: Properly handles newlines and spacing
4. Smart file management:
   • Removes entire file if only shebang/comments remain
   • Preserves file with remaining hook logic

Example Scenarios

Scenario 1: No Existing Hook

$ git-pair add John Doe john@example.com

Result: Creates new hook file with shebang and git-pair section

Scenario 2: Existing Hook Present

# Existing hook content
#!/bin/sh
echo "Custom hook logic"

After git-pair add John Doe john@example.com:

#!/bin/sh
echo "Custom hook logic"

# BEGIN git-pair
# git-pair hook to automatically add co-authors
# ... git-pair logic ...
# END git-pair

Scenario 3: Clearing Co-authors

When running git-pair clear:

• If other hook logic exists: Removes only git-pair section, preserves rest
• If only git-pair content: Removes entire hook file

Benefits

1. Backward Compatibility: Existing hooks continue to work without modification
2. Team Integration: Multiple team members can use git-pair without conflicts
3. Tool Interoperability: Works alongside other tools that use prepare-commit-msg hooks
4. Safe Operations: All operations are reversible and non-destructive

Testing

The implementation includes comprehensive tests covering:

• Hook preservation workflows
• Section merging and replacement
• Complete hook removal scenarios
• Integration with existing hook content
• Edge cases (empty hooks, comment-only hooks, etc.)

All tests pass and the functionality has been validated through both unit tests and integration tests.