Code review fixes.

Author: Oleh Kozynets

pandas/io/parsers.py

@@ -613,8 +613,7 @@ def read_csv(
     # the comparison to dialect values by checking if default values
     # for BOTH "delimiter" and "sep" were provided.
     if dialect is not None:
-        sep_override = (delimiter is None) and (sep is lib.no_default
-                                                or sep == ",")
+        sep_override = (delimiter is None) and (sep is lib.no_default or sep == ",")
         kwds = dict(sep_override=sep_override)
     else:
         kwds = dict()

pandas/tests/io/parser/test_common.py

@@ -2211,7 +2211,8 @@ def test_read_table_delim_whitespace_default_sep(all_parsers):
     tm.assert_frame_equal(result, expected)
 
 
-def test_read_csv_delim_whitespace_non_default_sep(all_parsers):
+@pytest.mark.parametrize("delimiter", [",", "\t"])
+def test_read_csv_delim_whitespace_non_default_sep(all_parsers, delimiter):
     # GH: 35958
     f = StringIO("a  b  c\n1 -2 -3\n4  5   6")
     parser = all_parsers
@@ -2220,13 +2221,14 @@ def test_read_csv_delim_whitespace_non_default_sep(all_parsers):
         "delim_whitespace=True; you can only specify one."
     )
     with pytest.raises(ValueError, match=msg):
-        parser.read_csv(f, delim_whitespace=True, sep="\t")
+        parser.read_csv(f, delim_whitespace=True, sep=delimiter)
 
     with pytest.raises(ValueError, match=msg):
-        parser.read_csv(f, delim_whitespace=True, delimiter="\t")
+        parser.read_csv(f, delim_whitespace=True, delimiter=delimiter)
 
 
-def test_read_table_delim_whitespace_non_default_sep(all_parsers):
+@pytest.mark.parametrize("delimiter", [",", "\t"])
+def test_read_table_delim_whitespace_non_default_sep(all_parsers, delimiter):
     # GH: 35958
     f = StringIO("a  b  c\n1 -2 -3\n4  5   6")
     parser = all_parsers
@@ -2235,37 +2237,8 @@ def test_read_table_delim_whitespace_non_default_sep(all_parsers):
         "delim_whitespace=True; you can only specify one."
     )
     with pytest.raises(ValueError, match=msg):
-        parser.read_table(f, delim_whitespace=True, sep=",")
+        parser.read_table(f, delim_whitespace=True, sep=delimiter)
 
     with pytest.raises(ValueError, match=msg):
-        parser.read_table(f, delim_whitespace=True, delimiter=",")
+        parser.read_table(f, delim_whitespace=True, delimiter=delimiter)
 
-
-def test_read_csv_delim_whitespace_explicit_default_sep(all_parsers):
-    # GH: 35958
-    f = StringIO("a  b  c\n1 -2 -3\n4  5   6")
-    parser = all_parsers
-    msg = (
-        "Specified a delimiter with both sep and "
-        "delim_whitespace=True; you can only specify one."
-    )
-    with pytest.raises(ValueError, match=msg):
-        parser.read_csv(f, delim_whitespace=True, sep=",")
-
-    with pytest.raises(ValueError, match=msg):
-        parser.read_csv(f, delim_whitespace=True, delimiter=",")
-
-
-def test_read_table_delim_whitespace_explicit_default_sep(all_parsers):
-    # GH: 35958
-    f = StringIO("a  b  c\n1 -2 -3\n4  5   6")
-    parser = all_parsers
-    msg = (
-        "Specified a delimiter with both sep and "
-        "delim_whitespace=True; you can only specify one."
-    )
-    with pytest.raises(ValueError, match=msg):
-        parser.read_table(f, delim_whitespace=True, sep="\t")
-
-    with pytest.raises(ValueError, match=msg):
-        parser.read_table(f, delim_whitespace=True, delimiter="\t")