Fixed #36341 -- Preserved whitespaces in wordwrap template filter.

Regression in 55d89e25f4115c5674cdd9b9bcba2bb2bb6d820b.

This work improves the django.utils.text.wrap() function to ensure that
empty lines and lines with whitespace only are kept instead of being
dropped.

Thanks Matti Pohjanvirta for the report and fix.

Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/tests/template_tests/filter_tests/test_wordwrap.py b/tests/template_tests/filter_tests/test_wordwrap.py
index 4afa1dd234..1692332e1e 100644
--- a/tests/template_tests/filter_tests/test_wordwrap.py
+++ b/tests/template_tests/filter_tests/test_wordwrap.py
@@ -89,3 +89,44 @@ class FunctionTests(SimpleTestCase):
             "I'm afraid",
             wordwrap(long_text, 10),
         )
+
+    def test_wrap_preserve_newlines(self):
+        cases = [
+            (
+                "this is a long paragraph of text that really needs to be wrapped\n\n"
+                "that is followed by another paragraph separated by an empty line\n",
+                "this is a long paragraph of\ntext that really needs to be\nwrapped\n\n"
+                "that is followed by another\nparagraph separated by an\nempty line\n",
+                30,
+            ),
+            ("\n\n\n", "\n\n\n", 5),
+            ("\n\n\n\n\n\n", "\n\n\n\n\n\n", 5),
+        ]
+        for text, expected, width in cases:
+            with self.subTest(text=text):
+                self.assertEqual(wordwrap(text, width), expected)
+
+    def test_wrap_preserve_whitespace(self):
+        width = 5
+        width_spaces = " " * width
+        cases = [
+            (
+                f"first line\n{width_spaces}\nsecond line",
+                f"first\nline\n{width_spaces}\nsecond\nline",
+            ),
+            (
+                "first line\n \t\t\t \nsecond line",
+                "first\nline\n \t\t\t \nsecond\nline",
+            ),
+            (
+                f"first line\n{width_spaces}\nsecond line\n\nthird{width_spaces}\n",
+                f"first\nline\n{width_spaces}\nsecond\nline\n\nthird\n",
+            ),
+            (
+                f"first line\n{width_spaces}{width_spaces}\nsecond line",
+                f"first\nline\n{width_spaces}{width_spaces}\nsecond\nline",
+            ),
+        ]
+        for text, expected in cases:
+            with self.subTest(text=text):
+                self.assertEqual(wordwrap(text, width), expected)