#15916: if there are no docstrings, make empty suite, not an error.
This makes doctest work like unittest: if the test case is empty, that
just means there are zero tests run, it's not an error. The existing
behavior was broken, since it only gave an error if there were *no*
docstrings, and zero tests run if there were docstrings but none of them
contained tests. So this makes it self-consistent as well.
Patch by Glenn Jones.
diff --git a/Doc/library/doctest.rst b/Doc/library/doctest.rst
index 50626e9..fb63fde 100644
--- a/Doc/library/doctest.rst
+++ b/Doc/library/doctest.rst
@@ -1058,15 +1058,9 @@
This function uses the same search technique as :func:`testmod`.
- .. note::
- Unlike :func:`testmod` and :class:`DocTestFinder`, this function raises
- a :exc:`ValueError` if *module* contains no docstrings. You can prevent
- this error by passing a :class:`DocTestFinder` instance as the
- *test_finder* argument with its *exclude_empty* keyword argument set
- to ``False``::
-
- >>> finder = doctest.DocTestFinder(exclude_empty=False)
- >>> suite = doctest.DocTestSuite(test_finder=finder)
+ .. versionchanged:: 3.5
+ :func:`DocTestSuite` returns an empty :class:`unittest.TestSuite` if *module*
+ contains no docstrings instead of raising :exc:`ValueError`.
Under the covers, :func:`DocTestSuite` creates a :class:`unittest.TestSuite` out
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
index 7050e0a..b9ad684 100644
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -154,6 +154,10 @@
applications where startup time is paramount (contributed by Brett Cannon in
:issue:`17621`).
+* :func:`doctest.DocTestSuite` returns an empty :class:`unittest.TestSuite` if
+ *module* contains no docstrings instead of raising :exc:`ValueError`
+ (contributed by Glenn Jones in :issue:`15916`).
+
Optimizations
=============