Commands: Set configuration file (for tests)

[tony]

Problem

Issue #472 requires session-scoped fixtures.

Currently, we use set_home, gitconfig, and hgconfig to monkeypatch.setenv $HOME, pointing it to a temporary directory with user-specific configuration files. This ensures all subsequent git and hg commands automatically load these configurations.

However, monkeypatch.setenv doesn't work with function-scoped fixtures.

Proposal

Environment Variables

• GIT_CONFIG
• HGRCPATH