#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/test/test_doctest.py b/Lib/test/test_doctest.py
index 9b500fd..8c87bee 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -2006,6 +2006,31 @@
>>> suite.run(unittest.TestResult())
<unittest.result.TestResult run=9 errors=0 failures=4>
+ The module need not contain any doctest examples:
+
+ >>> suite = doctest.DocTestSuite('test.sample_doctest_no_doctests')
+ >>> suite.run(unittest.TestResult())
+ <unittest.result.TestResult run=0 errors=0 failures=0>
+
+ However, if DocTestSuite finds no docstrings, it raises an error:
+
+ >>> try:
+ ... doctest.DocTestSuite('test.sample_doctest_no_docstrings')
+ ... except ValueError as e:
+ ... error = e
+
+ >>> print(error.args[1])
+ has no docstrings
+
+ You can prevent this error by passing a DocTestFinder instance with
+ the `exclude_empty` keyword argument set to False:
+
+ >>> finder = doctest.DocTestFinder(exclude_empty=False)
+ >>> suite = doctest.DocTestSuite('test.sample_doctest_no_docstrings',
+ ... test_finder=finder)
+ >>> suite.run(unittest.TestResult())
+ <unittest.result.TestResult run=0 errors=0 failures=0>
+
We can use the current module:
>>> suite = test.sample_doctest.test_suite()