diff --git a/lib/spack/spack/test/conftest.py b/lib/spack/spack/test/conftest.py
index 1772d7bdd08..56b67ae0e57 100644
--- a/lib/spack/spack/test/conftest.py
+++ b/lib/spack/spack/test/conftest.py
@@ -1539,10 +1539,10 @@ def get_rev():
 
 
 @pytest.fixture()
-def mutable_mock_env_path(tmpdir_factory, mutable_config):
+def mutable_mock_env_path(tmpdir, mutable_config):
     """Fixture for mocking the internal spack environments directory."""
     saved_path = ev.environment.default_env_path
-    mock_path = tmpdir_factory.mktemp("mock-env-path")
+    mock_path = tmpdir.join("mock-env-path")
     ev.environment.default_env_path = str(mock_path)
     yield mock_path
     ev.environment.default_env_path = saved_path