Require SciPy >= 1.4 in `TestGmres`
scipy/scipy#10341 added the `callback_type` arg.
@@ -404,7 +404,7 @@ class TestCg(unittest.TestCase):
'b_ndim': [1, 2],
'restart': [None, 10],
}))
-@unittest.skipUnless(scipy_available, 'requires scipy')
+@testing.with_requires('scipy>=1.4')
@testing.gpu
class TestGmres(unittest.TestCase):
n = 30
