Add a test when multiple classes are specified in warns

testing/test_recwarn.py

@@ -247,6 +247,17 @@ def test_record_by_subclass(self):
         assert str(record[0].message) == "user"
         assert str(record[1].message) == "runtime"
 
+        class MyUserWarning(UserWarning): pass
+        class MyRuntimeWarning(RuntimeWarning): pass
+
+        with pytest.warns((UserWarning, RuntimeWarning)) as record:
+            warnings.warn("user", MyUserWarning)
+            warnings.warn("runtime", MyRuntimeWarning)
+
+        assert len(record) == 2
+        assert str(record[0].message) == "user"
+        assert str(record[1].message) == "runtime"
+
 
     def test_double_test(self, testdir):
         """If a test is run again, the warning should still be raised"""