diff --git a/mne/viz/tests/test_circle.py b/mne/viz/tests/test_circle.py
index a92e672db28..c5f3719746b 100644
--- a/mne/viz/tests/test_circle.py
+++ b/mne/viz/tests/test_circle.py
@@ -17,7 +17,7 @@ def test_plot_channel_labels_circle():
     fig, axes = plot_channel_labels_circle(
         dict(brain=["big", "great", "smart"]),
         colors=dict(big="r", great="y", smart="b"),
-        colorbar=True
+        colorbar=True,
     )
     # check that colorbar handle is returned
     assert isinstance(fig.mne.colorbar, matplotlib.colorbar.Colorbar)