test: add unit tests for core, parser and operations

tests/test_inventory.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from sshctl.export.inventory import _to_group_name, generate_inventory
+
+
+def test_to_group_name_simple() -> None:
+    assert _to_group_name("internal") == "internal"
+    assert _to_group_name("cluster1") == "cluster1"
+
+
+def test_to_group_name_with_hyphens() -> None:
+    assert _to_group_name("8xx-serverfarm") == "z8xx_serverfarm"
+
+
+def test_to_group_name_starts_with_digit() -> None:
+    assert _to_group_name("8xx") == "z8xx"
+
+
+def test_generate_inventory_no_ssh_dir(tmp_path: Path) -> None:
+    result = generate_inventory(tmp_path / "nonexistent")
+    assert result == {}
+
+
+def test_generate_inventory_empty_config(tmp_path: Path) -> None:
+    ssh_dir = tmp_path / ".ssh"
+    ssh_dir.mkdir()
+    (ssh_dir / "config").write_text("Host *\n  User root\n")
+    result = generate_inventory(ssh_dir)
+    assert result == {}