Backport PR #42174: TST/CI: speed up chunksize test (#42182)

Co-authored-by: Matthew Zeitlin <37011898+mzeitlin11@users.noreply.github.com>

Author: meeseeksmachine

pandas/tests/io/parser/common/test_chunksize.py

@@ -177,34 +177,22 @@ def test_chunks_have_consistent_numerical_type(all_parsers):
 def test_warn_if_chunks_have_mismatched_type(all_parsers, request):
     warning_type = None
     parser = all_parsers
-    integers = [str(i) for i in range(499999)]
-    data = "a\n" + "\n".join(integers + ["a", "b"] + integers)
+    size = 10000
 
     # see gh-3866: if chunks are different types and can't
     # be coerced using numerical types, then issue warning.
     if parser.engine == "c" and parser.low_memory:
         warning_type = DtypeWarning
+        # Use larger size to hit warning path
+        size = 499999
+
+    integers = [str(i) for i in range(size)]
+    data = "a\n" + "\n".join(integers + ["a", "b"] + integers)
 
     buf = StringIO(data)
 
-    try:
-        with tm.assert_produces_warning(warning_type):
-            df = parser.read_csv(buf)
-    except AssertionError as err:
-        # 2021-02-21 this occasionally fails on the CI with an unexpected
-        #  ResourceWarning that we have been unable to track down,
-        #  see GH#38630
-        if "ResourceWarning" not in str(err) or parser.engine != "python":
-            raise
-
-        # Check the main assertion of the test before re-raising
-        assert df.a.dtype == object
-
-        mark = pytest.mark.xfail(
-            reason="ResourceWarning for unclosed SSL Socket, GH#38630"
-        )
-        request.node.add_marker(mark)
-        raise
+    with tm.assert_produces_warning(warning_type):
+        df = parser.read_csv(buf)
 
     assert df.a.dtype == object