bpo-32255: Always quote a single empty field when write into a CSV file. (#4769)
This allows to distinguish an empty row from a row consisting of a single empty field.
diff --git a/Lib/test/test_csv.py b/Lib/test/test_csv.py
index 03ab184..fe24801 100644
--- a/Lib/test/test_csv.py
+++ b/Lib/test/test_csv.py
@@ -207,10 +207,29 @@
with TemporaryFile("w+", newline='') as fileobj:
writer = csv.writer(fileobj)
self.assertRaises(TypeError, writer.writerows, None)
- writer.writerows([['a','b'],['c','d']])
+ writer.writerows([['a', 'b'], ['c', 'd']])
fileobj.seek(0)
self.assertEqual(fileobj.read(), "a,b\r\nc,d\r\n")
+ def test_writerows_with_none(self):
+ with TemporaryFile("w+", newline='') as fileobj:
+ writer = csv.writer(fileobj)
+ writer.writerows([['a', None], [None, 'd']])
+ fileobj.seek(0)
+ self.assertEqual(fileobj.read(), "a,\r\n,d\r\n")
+
+ with TemporaryFile("w+", newline='') as fileobj:
+ writer = csv.writer(fileobj)
+ writer.writerows([[None], ['a']])
+ fileobj.seek(0)
+ self.assertEqual(fileobj.read(), '""\r\na\r\n')
+
+ with TemporaryFile("w+", newline='') as fileobj:
+ writer = csv.writer(fileobj)
+ writer.writerows([['a'], [None]])
+ fileobj.seek(0)
+ self.assertEqual(fileobj.read(), 'a\r\n""\r\n')
+
@support.cpython_only
def test_writerows_legacy_strings(self):
import _testcapi