issue9859: Document test.support.detect_api_mismatch() and simplify its test.

1 files changed, 9 insertions, 0 deletions

diff --git a/Doc/library/test.rst b/Doc/library/test.rst
index 974909e..029f930 100644
--- a/Doc/library/test.rst
+++ b/Doc/library/test.rst
@@ -568,6 +568,15 @@ The :mod:`test.support` module defines the following functions:
       def load_tests(*args):
           return load_package_tests(os.path.dirname(__file__), *args)
 
+.. function:: detect_api_mismatch(ref_api, other_api, *, ignore=()):
+
+   Returns the set of attributes, functions or methods of `ref_api` not
+   found on `other_api`, except for a defined list of items to be
+   ignored in this check specified in `ignore`.
+
+   By default this skips private attributes beginning with '_' but
+   includes all magic methods, i.e. those starting and ending in '__'.
+
 
 The :mod:`test.support` module defines the following classes: