diff --git a/src/darker/tests/test_command_line.py b/src/darker/tests/test_command_line.py
index 7f359f1a4..3b85132b5 100644
--- a/src/darker/tests/test_command_line.py
+++ b/src/darker/tests/test_command_line.py
@@ -621,11 +621,11 @@ def test_black_options(monkeypatch, tmpdir, git_repo, options, expect):
     dict(options=["--preview"], expect_opts=["--preview"]),
     expect_opts=[],
 )
-def test_ruff_options(monkeypatch, tmpdir, git_repo, options, expect_opts):
+def test_ruff_options(monkeypatch, tmp_path, git_repo, options, expect_opts):
     """Ruff options from the command line are passed correctly to Ruff."""
-    monkeypatch.chdir(tmpdir)
-    (tmpdir / "pyproject.toml").write("[tool.ruff]\n")
-    (tmpdir / "ruff.cfg").write(
+    monkeypatch.chdir(tmp_path)
+    (tmp_path / "pyproject.toml").write_text("[tool.ruff]\n")
+    (tmp_path / "ruff.cfg").write_text(
         dedent(
             """
             [tool.ruff]