ignore delimiter warnings where appropriate

Author: minggli

pandas/io/parsers.py

@@ -641,7 +641,7 @@ def parser_f(filepath_or_buffer,
         else:
             # GH 21996
             warnings.warn("delimiter is deprecated, use sep instead.",
-                          FutureWarning, stacklevel=2)
+                          FutureWarning, stacklevel=4)
 
         if delim_whitespace and delimiter != default_sep:
             raise ValueError("Specified a delimiter with both sep and"

pandas/tests/io/parser/c_parser_only.py

@@ -410,6 +410,7 @@ def test_data_after_quote(self):
         tm.assert_frame_equal(result, expected)
 
     @tm.capture_stderr
+    @pytest.mark.filterwarnings('ignore::FutureWarning')
     def test_comment_whitespace_delimited(self):
         test_input = """\
 1 2

pandas/tests/io/parser/python_parser_only.py

@@ -47,6 +47,7 @@ def test_invalid_skipfooter(self):
         with tm.assert_raises_regex(ValueError, msg):
             self.read_csv(StringIO(text), skipfooter=-1)
 
+    @pytest.mark.filterwarnings('ignore::FutureWarning')
     def test_sniff_delimiter(self):
         text = """index|A|B|C
 foo|1|2|3