MAINT: Replace use of pytest.warns(None) with warnings.catch_warnings

scipy/fft/tests/test_fftlog.py

@@ -1,3 +1,4 @@
+import warnings
 import numpy as np
 from numpy.testing import assert_allclose
 import pytest
@@ -108,13 +109,13 @@ def test_fht_special_cases():
 
     # case 1: xp in M, xm in M => well-defined transform
     mu, bias = -4.0, 1.0
-    with pytest.warns(None) as record:
+    with warnings.catch_warnings(record=True) as record:
         fht(a, dln, mu, bias=bias)
         assert not record, 'fht warned about a well-defined transform'
 
     # case 2: xp not in M, xm in M => well-defined transform
     mu, bias = -2.5, 0.5
-    with pytest.warns(None) as record:
+    with warnings.catch_warnings(record=True) as record:
         fht(a, dln, mu, bias=bias)
         assert not record, 'fht warned about a well-defined transform'
 

scipy/sparse/csgraph/tests/test_shortest_path.py

@@ -1,3 +1,4 @@
+import warnings
 import numpy as np
 from numpy.testing import assert_array_almost_equal, assert_array_equal
 from pytest import raises as assert_raises
@@ -118,6 +119,7 @@ def check(method, directed_in):
         for directed_in in (True, False):
             check(method, directed_in)
 
+
 def test_directed_sparse_zero():
     # test directed sparse graph with zero-weight edge and two connected components
     def check(method):
@@ -128,6 +130,7 @@ def check(method):
     for method in methods:
         check(method)
 
+
 def test_undirected_sparse_zero():
     def check(method, directed_in):
         if directed_in:
@@ -312,7 +315,7 @@ def test_buffer(method):
 
 
 def test_NaN_warnings():
-    with pytest.warns(None) as record:
+    with warnings.catch_warnings(record=True) as record:
         shortest_path(np.array([[0, 1], [np.nan, 0]]))
     for r in record:
         assert r.category is not RuntimeWarning