Issue #21827: Fixed textwrap.dedent() for the case when largest common
whitespace is a substring of smallest leading whitespace.
Based on patch by Robert Li.
diff --git a/Lib/test/test_textwrap.py b/Lib/test/test_textwrap.py
index 7b72672..dccf095 100644
--- a/Lib/test/test_textwrap.py
+++ b/Lib/test/test_textwrap.py
@@ -647,6 +647,11 @@
expect = "hello there\n how are you?"
self.assertEqual(expect, dedent(text))
+ # test margin is smaller than smallest indent
+ text = " \thello there\n \thow are you?\n \tI'm fine, thanks"
+ expect = " \thello there\n \thow are you?\n\tI'm fine, thanks"
+ self.assertEqual(expect, dedent(text))
+
def test_main():
test_support.run_unittest(WrapTestCase,