Add OP test

Author: roberthdevries

pandas/tests/tools/test_to_numeric.py

@@ -633,3 +633,7 @@ def test_failure_to_convert_uint64_string_to_NaN():
     # GH 32394
     result = to_numeric("uint64", errors="coerce")
     assert np.isnan(result)
+
+    ser = Series([32, 64, np.nan])
+    result = to_numeric(pd.Series(["32", "64", "uint64"]), errors="coerce")
+    tm.assert_series_equal(result, ser)