chore: Add unit tests to git module

.gitignore

@@ -12,3 +12,4 @@ tests/fixtures/sample-workspace
 .coverage
 coverage.xml
 htmlcov
+junit.xml

tests/test_git.py

@@ -0,0 +1,47 @@
+import tempfile
+from pathlib import Path
+import git
+import pytest
+import bough.git as sut
+
+
+@pytest.fixture
+def git_repo():
+    """Create a temporary git repo for testing."""
+    with tempfile.TemporaryDirectory() as tmpdir:
+        repo_path = Path(tmpdir) / "guardians"
+        repo = git.Repo.init(repo_path)
+
+        (repo_path / "members.txt").write_text("star-lord\n")
+        (repo_path / "README.txt").write_text("TODO")
+        repo.index.add(["members.txt", "README.txt"])
+        repo.index.commit("Initial commit")
+
+        yield repo_path, repo
+
+
+def test_finds_various_changed_files(git_repo):
+    """Test detection of committed, staged, unstaged, and untracked changes."""
+    repo_path, repo = git_repo
+    base_commit = repo.head.commit.hexsha
+
+    (repo_path / "members.txt").write_text("rocky raccoon\ngroot\n")
+    repo.index.add(["members.txt"])
+    repo.index.commit("Add members")
+
+    (repo_path / "enemies.txt").write_text("nova core\n")
+    (repo_path / "members.txt").write_text("gamora\n")
+    repo.index.add(["enemies.txt", "members.txt"])
+
+    (repo_path / "powers.txt").write_text("awesomeness\n")
+    (repo_path / "assets.txt").write_text("infinity stone\n")
+
+    files = sut.find_changed_files(repo_path, base_commit)
+    assert files == {"members.txt", "enemies.txt", "powers.txt", "assets.txt"}
+
+    repo.index.commit("Add members and enemies")
+    (repo_path / "README.txt").write_text("A little bit of both...\n")
+    repo.index.add(["powers.txt"])
+
+    files = sut.find_changed_files(repo_path, repo.head.commit.hexsha)
+    assert files == {"powers.txt", "assets.txt", "README.txt"}