Add args tests.

Author: fabiocaccamo

fsutil/args.py

@@ -6,6 +6,8 @@
 
 
 def get_path(path: PathIn) -> str:
+    if path is None:
+        return None
     if isinstance(path, str):
         return os.path.normpath(path)
     return str(path)

tests/test_args.py

@@ -0,0 +1,29 @@
+import os
+from pathlib import Path
+
+import pytest
+
+from fsutil.args import get_path
+
+
+@pytest.mark.parametrize(
+    "input_path, expected",
+    [
+        (None, None),
+        ("", "."),
+        ("/home/user/docs", os.path.normpath("/home/user/docs")),
+        ("C:\\Users\\test", os.path.normpath("C:\\Users\\test")),
+        ("./relative/path", os.path.normpath("./relative/path")),
+        ("..", os.path.normpath("..")),
+        (Path("/home/user/docs"), os.path.normpath("/home/user/docs")),
+        (Path("C:\\Users\\test"), os.path.normpath("C:\\Users\\test")),
+        (Path("./relative/path"), os.path.normpath("./relative/path")),
+        (Path(".."), os.path.normpath("..")),
+    ],
+)
+def test_get_path(input_path, expected):
+    assert get_path(input_path) == expected
+
+
+if __name__ == "__main__":
+    pytest.main()