bpo-30825: guess lineterminator in csv.Sniffer by vmax · Pull Request #2529 · python/cpython · GitHub
Skip to content

bpo-30825: guess lineterminator in csv.Sniffer #2529

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
vmax wants to merge 2 commits into from
Closed

bpo-30825: guess lineterminator in csv.Sniffer #2529

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
6f46019
bpo-30825: guess lineterminator in csv.Sniffer
vmax Jul 1, 2017
524ff18
Fix unit test to cover weird or no terminator case (os.linesep)
vmax Feb 12, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 19 additions & 5 deletions Lib/csv.py
View file
Open in desktop
15 changes: 15 additions & 0 deletions Lib/test/test_csv.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
import csv
import gc
import pickle
import os
from test import support
from itertools import permutations
from textwrap import dedent
Expand Down Expand Up @@ -1018,6 +1019,20 @@ def test_doublequote(self):
dialect = sniffer.sniff(self.sample9)
self.assertTrue(dialect.doublequote)

def test_guess_lineterminator(self):
sniffer = csv.Sniffer()
dialect = sniffer.sniff(r"Date;Value\r\n2010-01-01;10")
self.assertEqual(dialect.lineterminator, '\r\n')
dialect = sniffer.sniff(r"Date;Value\n2010-01-01;10")
self.assertEqual(dialect.lineterminator, '\n')

@terryjreedy terryjreedy Feb 7, 2018

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This assumes that the line terminator for multiline triple-quoted string literals is '\n'. We require that '\r\n' in code files be converted to '\n' before merging, but the test should not assume '\n' for all developer and user systems where the test might be run. So sample8 should be replaced by a literal.

Since the sample strings need not be long, they can all be literals defined here. Make all 3 the same except for the terminator. This will make the test both crystal clear and independent of system and optional local settings.

dialect = sniffer.sniff(r"Date;Value\r2010-01-01;10")
self.assertEqual(dialect.lineterminator, '\r')
dialect = sniffer.sniff(r"Date;Value\v2010-01-01;10")
self.assertEqual(dialect.lineterminator, os.linesep)
dialect = sniffer.sniff(r"Date;Value")
self.assertEqual(dialect.lineterminator, os.linesep)

@terryjreedy terryjreedy Feb 7, 2018

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Add tests to cover the last line of _guess_lineterminator: return os.linesep. Add a test with the same literal, but with an oddball terminator, such as '\v' (vertical tab), and another with a single line with no control chars.


class NUL:
def write(s, *args):
pass
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2018-02-12-05-10-28.bpo-30825.t0RXql.rst
View file
Open in desktop