summarize warning summaries if the number of locations is high

testing/example_scripts/warnings/test_group_warnings_by_message_summary.py

@@ -0,0 +1,21 @@
+import warnings
+
+import pytest
+
+
+def func():
+    warnings.warn(UserWarning("foo"))
+
+
+@pytest.fixture(params=range(20), autouse=True)
+def repeat_hack(request):
+    return request.param
+
+
+@pytest.mark.parametrize("i", range(5))
+def test_foo(i):
+    func()
+
+
+def test_bar():
+    func()