#14649: clarify DocTestSuite error when there are no docstrings.
Also adds tests to verify the documented behavior (which is probably a bug, as
indicated in the added comments).
Patch by Chris Jerdonek.
diff --git a/Lib/doctest.py b/Lib/doctest.py
index 095f560..90bcca1 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -2381,7 +2381,12 @@
elif not tests:
# Why do we want to do this? Because it reveals a bug that might
# otherwise be hidden.
- raise ValueError(module, "has no tests")
+ # It is probably a bug that this exception is not also raised if the
+ # number of doctest examples in tests is zero (i.e. if no doctest
+ # examples were found). However, we should probably not be raising
+ # an exception at all here, though it is too late to make this change
+ # for a maintenance release. See also issue #14649.
+ raise ValueError(module, "has no docstrings")
tests.sort()
suite = unittest.TestSuite()