Add full test suite with pytest

tests/test_scan.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import stat
+from pathlib import Path
+
+from chguard.scan import scan_tree
+
+
+def entries_by_path(root: Path, excludes: tuple[str, ...] = ()):
+    return {entry.path: entry for entry in scan_tree(root, excludes=excludes)}
+
+
+def test_scan_tree_records_root_dirs_files_and_symlinks(
+    tmp_path: Path,
+) -> None:
+    root = tmp_path / "root"
+    root.mkdir()
+    data_dir = root / "data"
+    data_dir.mkdir()
+    file_path = data_dir / "config.txt"
+    file_path.write_text("config", encoding="utf-8")
+    file_path.chmod(0o640)
+    (root / "config-link").symlink_to(file_path)
+
+    entries = entries_by_path(root)
+
+    assert entries[""].type == "dir"
+    assert entries["data"].type == "dir"
+    assert entries["data/config.txt"].type == "file"
+    assert entries["data/config.txt"].mode == 0o640
+    assert entries["config-link"].type == "symlink"
+    assert entries["config-link"].mode == stat.S_IMODE(
+        (root / "config-link").lstat().st_mode
+    )
+
+
+def test_scan_tree_excludes_path_prefixes(tmp_path: Path) -> None:
+    root = tmp_path / "root"
+    root.mkdir()
+    (root / "keep").mkdir()
+    (root / "keep" / "file.txt").write_text("keep", encoding="utf-8")
+    (root / "cache").mkdir()
+    (root / "cache" / "file.txt").write_text("cache", encoding="utf-8")
+    (root / "var").mkdir()
+    (root / "var" / "tmp").mkdir()
+    (root / "var" / "tmp" / "file.txt").write_text("tmp", encoding="utf-8")
+
+    entries = entries_by_path(root, excludes=("cache", "var/tmp"))
+
+    assert "keep" in entries
+    assert "keep/file.txt" in entries
+    assert "cache" not in entries
+    assert "cache/file.txt" not in entries
+    assert "var" in entries
+    assert "var/tmp" not in entries
+    assert "var/tmp/file.txt" not in entries
+
+
+def test_scan_tree_file_root_records_only_root_entry(tmp_path: Path) -> None:
+    root_file = tmp_path / "single.txt"
+    root_file.write_text("single", encoding="utf-8")
+
+    entries = list(scan_tree(root_file))
+
+    assert len(entries) == 1
+    assert entries[0].path == ""
+    assert entries[0].type == "file"