fix: auto-stash local changes during updates

tests/hermes_cli/test_update_autostash.py

@@ -0,0 +1,102 @@
+from pathlib import Path
+from subprocess import CalledProcessError
+from types import SimpleNamespace
+
+import pytest
+
+from hermes_cli import main as hermes_main
+
+
+def test_stash_local_changes_if_needed_returns_none_when_tree_clean(monkeypatch, tmp_path):
+    calls = []
+
+    def fake_run(cmd, **kwargs):
+        calls.append((cmd, kwargs))
+        if cmd[-2:] == ["status", "--porcelain"]:
+            return SimpleNamespace(stdout="", returncode=0)
+        raise AssertionError(f"unexpected command: {cmd}")
+
+    monkeypatch.setattr(hermes_main.subprocess, "run", fake_run)
+
+    stash_ref = hermes_main._stash_local_changes_if_needed(["git"], tmp_path)
+
+    assert stash_ref is None
+    assert [cmd[-2:] for cmd, _ in calls] == [["status", "--porcelain"]]
+
+
+def test_stash_local_changes_if_needed_returns_specific_stash_commit(monkeypatch, tmp_path):
+    calls = []
+
+    def fake_run(cmd, **kwargs):
+        calls.append((cmd, kwargs))
+        if cmd[-2:] == ["status", "--porcelain"]:
+            return SimpleNamespace(stdout=" M hermes_cli/main.py\n?? notes.txt\n", returncode=0)
+        if cmd[1:4] == ["stash", "push", "--include-untracked"]:
+            return SimpleNamespace(stdout="Saved working directory\n", returncode=0)
+        if cmd[-3:] == ["rev-parse", "--verify", "refs/stash"]:
+            return SimpleNamespace(stdout="abc123\n", returncode=0)
+        raise AssertionError(f"unexpected command: {cmd}")
+
+    monkeypatch.setattr(hermes_main.subprocess, "run", fake_run)
+
+    stash_ref = hermes_main._stash_local_changes_if_needed(["git"], tmp_path)
+
+    assert stash_ref == "abc123"
+    assert calls[1][0][1:4] == ["stash", "push", "--include-untracked"]
+    assert calls[2][0][-3:] == ["rev-parse", "--verify", "refs/stash"]
+
+
+def test_restore_stashed_changes_applies_specific_stash_and_drops_it(monkeypatch, tmp_path, capsys):
+    calls = []
+
+    def fake_run(cmd, **kwargs):
+        calls.append((cmd, kwargs))
+        if cmd[1:3] == ["stash", "apply"]:
+            return SimpleNamespace(stdout="applied\n", stderr="", returncode=0)
+        if cmd[1:3] == ["stash", "drop"]:
+            return SimpleNamespace(stdout="dropped\n", stderr="", returncode=0)
+        raise AssertionError(f"unexpected command: {cmd}")
+
+    monkeypatch.setattr(hermes_main.subprocess, "run", fake_run)
+
+    hermes_main._restore_stashed_changes(["git"], tmp_path, "abc123")
+
+    assert calls[0][0] == ["git", "stash", "apply", "abc123"]
+    assert calls[1][0] == ["git", "stash", "drop", "abc123"]
+    assert "Restoring local changes" in capsys.readouterr().out
+
+
+def test_restore_stashed_changes_exits_cleanly_when_apply_fails(monkeypatch, tmp_path, capsys):
+    calls = []
+
+    def fake_run(cmd, **kwargs):
+        calls.append((cmd, kwargs))
+        if cmd[1:3] == ["stash", "apply"]:
+            return SimpleNamespace(stdout="conflict output\n", stderr="conflict stderr\n", returncode=1)
+        raise AssertionError(f"unexpected command: {cmd}")
+
+    monkeypatch.setattr(hermes_main.subprocess, "run", fake_run)
+
+    with pytest.raises(SystemExit, match="1"):
+        hermes_main._restore_stashed_changes(["git"], tmp_path, "abc123")
+
+    out = capsys.readouterr().out
+    assert "Your changes are still preserved in git stash." in out
+    assert "git stash apply abc123" in out
+    assert calls == [(["git", "stash", "apply", "abc123"], {"cwd": tmp_path, "capture_output": True, "text": True})]
+
+
+def test_stash_local_changes_if_needed_raises_when_stash_ref_missing(monkeypatch, tmp_path):
+    def fake_run(cmd, **kwargs):
+        if cmd[-2:] == ["status", "--porcelain"]:
+            return SimpleNamespace(stdout=" M hermes_cli/main.py\n", returncode=0)
+        if cmd[1:4] == ["stash", "push", "--include-untracked"]:
+            return SimpleNamespace(stdout="Saved working directory\n", returncode=0)
+        if cmd[-3:] == ["rev-parse", "--verify", "refs/stash"]:
+            raise CalledProcessError(returncode=128, cmd=cmd)
+        raise AssertionError(f"unexpected command: {cmd}")
+
+    monkeypatch.setattr(hermes_main.subprocess, "run", fake_run)
+
+    with pytest.raises(CalledProcessError):
+        hermes_main._stash_local_changes_if_needed(["git"], Path(tmp_path))