changeset:   96707:b784c842a63c
branch:      3.4
user:        Jason R. Coombs <jaraco@jaraco.com>
date:        Sat Jun 20 19:52:22 2015 -0400
files:       Lib/test/test_tokenize.py
description:
Issue #20387: Add test capturing failure to roundtrip indented code in tokenize module.


diff -r 8bf1c158332f -r b784c842a63c Lib/test/test_tokenize.py
--- a/Lib/test/test_tokenize.py	Sat Jun 20 19:13:50 2015 -0400
+++ b/Lib/test/test_tokenize.py	Sat Jun 20 19:52:22 2015 -0400
@@ -1229,6 +1229,22 @@
         self.assertEqual(untokenize(iter(tokens)), b'Hello ')
 
 
+class TestRoundtrip(TestCase):
+    def roundtrip(self, code):
+        if isinstance(code, str):
+            code = code.encode('utf-8')
+        return untokenize(tokenize(BytesIO(code).readline))
+
+    def test_indentation_semantics_retained(self):
+        """
+        Ensure that although whitespace might be mutated in a roundtrip,
+        the semantic meaning of the indentation remains consistent.
+        """
+        code = "if False:\n\tx=3\n\tx=3\n"
+        codelines = roundtrip(code).split('\n')
+        self.assertEqual(codelines[1], codelines[2])
+
+
 __test__ = {"doctests" : doctests, 'decistmt': decistmt}
 
 def test_main():
@@ -1239,6 +1255,7 @@
     support.run_unittest(TestDetectEncoding)
     support.run_unittest(TestTokenize)
     support.run_unittest(UntokenizeTest)
+    support.run_unittest(TestRoundtrip)
 
 if __name__ == "__main__":
     test_main()