ELLIPSIS implementation: an ellipsis couldn't match nothing if it
appeared at the end of a line. Repaired that. Also noted that it's
too easy to provoke this implementation into requiring exponential
time, and especially when a test fails. I'll replace the implementation
with an always-efficient one later.
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
index dec9110..d49e6cf 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -780,6 +780,29 @@
>>> doctest.DocTestRunner(verbose=False, optionflags=flags).run(test)
(0, 1)
+... should also match nothing gracefully:
+XXX This can be provoked into requiring exponential time by adding more
+XXX ellipses; the implementation should change. It's much easier to
+XXX provoke exponential time with expected output that doesn't match,
+XXX BTW (then multiple regexp .* thingies each try all possiblities,
+XXX multiplicatively, without hope of success). That's the real danger,
+XXX that a failing test will appear to be hung.
+
+ >>> for i in range(100):
+ ... print i**2 #doctest: +ELLIPSIS
+ 0
+ ...
+ 1
+ ...
+ 36
+ ...
+ ...
+ 49
+ 64
+ ......
+ 9801
+ ...
+
The UNIFIED_DIFF flag causes failures that involve multi-line expected
and actual outputs to be displayed using a unified diff: