diff --git a/tests/functional2/pyproject.toml b/tests/functional2/pyproject.toml
index d807b996e..2c8a2122c 100644
--- a/tests/functional2/pyproject.toml
+++ b/tests/functional2/pyproject.toml
@@ -5,6 +5,12 @@ requires-python = ">=3.11"
 
 [tool.pytest.ini_options]
 addopts = "-p no:xonsh"
+
+# Keep the temporary files of the last 3 test runs (default value)
+tmp_path_retention_count = 3
+# Keep temporary files of all tests, regardless if they failed or not
+tmp_path_retention_policy = "all"
+
 log_cli = true
 log_cli_level = "INFO"
 # how the logs are being printed, default is `"%(filename)s %(lineno)d %(levelname)s %(message)s"`
diff --git a/tests/functional2/testlib/fixtures/nix.py b/tests/functional2/testlib/fixtures/nix.py
index c893c76e2..63ce1d176 100644
--- a/tests/functional2/testlib/fixtures/nix.py
+++ b/tests/functional2/testlib/fixtures/nix.py
@@ -6,7 +6,7 @@ import subprocess
 from functools import partialmethod
 from pathlib import Path
 from typing import Any, AnyStr
-from collections.abc import Callable
+from collections.abc import Callable, Generator
 
 import pytest
 
@@ -239,5 +239,9 @@ class Nix:
 
 
 @pytest.fixture
-def nix(tmp_path: Path) -> Nix:
-    return Nix(tmp_path)
+def nix(tmp_path: Path) -> Generator[Nix, Any, None]:
+    yield Nix(tmp_path)
+    # when things are done using the nix store, the permissions for the store are read only
+    # after the test was executed, we set the permissions to rwx (write being the important part)
+    # for pytest to be able to delete the files during cleanup
+    Command(argv=["chmod", "-R", "+w", str(tmp_path.absolute())], env=os.environ.copy()).run().ok()