fix: unit test on github's macOs action runner

Somehow, the tmp directory is a symlink on github.

tests/commands/test_local.py

@@ -1,4 +1,5 @@
 import os
+import pathlib
 import tempfile
 import unittest
 from unittest.mock import patch
@@ -27,6 +28,8 @@ class LocalTests(unittest.TestCase, TestCommandMixin):
     def test_copyfrom(self) -> None:
         with temporary_root() as root:
             with tempfile.TemporaryDirectory() as directory:
+                # resolve actual path, just like click.Path does it.
+                directory = os.fsdecode(pathlib.Path(directory).resolve())
                 with patch("tutor.utils.docker_compose") as mock_docker_compose:
                     self.invoke_in_root(root, ["config", "save"])