Issue #22002: Make full use of test discovery in test sub-packages.

Adds `load_package_tests` function to test.support, uses it in test_asyncio,
test_email, test_json, test_tools, test_importlib and all test_importlib
sub-packages to implement test discovery.

1 files changed, 16 insertions, 1 deletions

diff --git a/Doc/library/test.rst b/Doc/library/test.rst
index 83026d8..7a7182a 100644
--- a/Doc/library/test.rst
+++ b/Doc/library/test.rst
@@ -461,7 +461,7 @@ The :mod:`test.support` module defines the following functions:
 .. function:: make_bad_fd()
 
    Create an invalid file descriptor by opening and closing a temporary file,
-   and returning its descripor.
+   and returning its descriptor.
 
 
 .. function:: import_module(name, deprecated=False)
@@ -554,6 +554,21 @@ The :mod:`test.support` module defines the following functions:
    run simultaneously, which is a problem for buildbots.
 
 
+.. function:: load_package_tests(pkg_dir, loader, standard_tests, pattern)
+
+   Generic implementation of the :mod:`unittest` ``load_tests`` protocol for
+   use in test packages.  *pkg_dir* is the root directory of the package;
+   *loader*, *standard_tests*, and *pattern* are the arguments expected by
+   ``load_tests``.  In simple cases, the test package's ``__init__.py``
+   can be the following::
+
+      import os
+      from test.support import load_package_tests
+
+      def load_tests(*args):
+          return load_package_tests(os.path.dirname(__file__), *args)
+
+
 The :mod:`test.support` module defines the following classes:
 
 .. class:: TransientResource(exc, **kwargs)