diff --git a/lib/spack/spack/test/conftest.py b/lib/spack/spack/test/conftest.py
index 617f6259ac9..7638ade00ce 100644
--- a/lib/spack/spack/test/conftest.py
+++ b/lib/spack/spack/test/conftest.py
@@ -1552,7 +1552,7 @@ def get_rev():
 
 
 @pytest.fixture()
-def mutable_mock_env_path(tmpdir_factory):
+def mutable_mock_env_path(tmpdir_factory, 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")