diff --git a/xarray/tests/test_concat.py b/xarray/tests/test_concat.py
index db46b363ac7..dee890d285b 100644
--- a/xarray/tests/test_concat.py
+++ b/xarray/tests/test_concat.py
@@ -659,7 +659,7 @@ def test_concat_errors(self):
 
         with pytest.raises(ValueError, match=r"compat.* invalid"):
             concat(split_data, "dim1", compat="foobar")
-        
+
         with pytest.raises(ValueError, match=r"compat.* invalid"):
             concat(split_data, "dim1", compat="minimal")