diff --git a/mhkit/tests/wave/test_resource_spectrum.py b/mhkit/tests/wave/test_resource_spectrum.py
index 61c15426..387f8718 100644
--- a/mhkit/tests/wave/test_resource_spectrum.py
+++ b/mhkit/tests/wave/test_resource_spectrum.py
@@ -159,7 +159,9 @@ def test_ifft_sum_of_sines(self):
 
         assert_allclose(eta_ifft, eta_sos)
 
-    def test_surface_elevation_uses_sum_of_sines_when_input_frequency_index_does_not_have_zero(self):
+    def test_surface_elevation_uses_sum_of_sines_when_input_frequency_index_does_not_have_zero(
+        self,
+    ):
         f = np.linspace(1 / 30, 1 / 2, 32)
         S = wave.resource.jonswap_spectrum(f, self.Tp, self.Hs)