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.

* Tulip issue 194: Don't use sys.getrefcount() in unit tests
* signal.set_wakeup_fd() can now raise an OSError on Python 3.5

* Tulip issue 194: Don't use sys.getrefcount() in unit tests
* signal.set_wakeup_fd() can now raise an OSError on Python 3.5

specified.

specified.

fully qualified class names of Python implemented classes.

coroutine

Replace also _make_drain_waiter() function with a classic _drain_helper()
coroutine.

Replace also _make_drain_waiter() function with a classic _drain_helper()
coroutine.

when contain an id in form " at 0x...".

now display special message when and only when there are failures.

now display special message when and only when there are failures.

Fix localhost checking in FileHandler. Raised in #21970.

Thanks to William Orr.

Thanks to William Orr.

Sort also imports in support/__init__.py

Sort also imports in support/__init__.py

* Issue #19811, #22022: test_pathlib uses support.rmtree() instead of
  shutil.rmtree() to remove the temporary directory.

* Issue #19629: Fix support.rmtree(), use os.lstat() to check if the file is a
  directory, not os.path.isdir()

shutil.rmtree() to remove the temporary directory.

directory, not os.path.isdir()

ValueError on fstat() failure.

- Use _testcapi.raise_signal() in test_signal
- close also os.pipe() file descriptors in some test_signal tests where they
  were not closed properly
- Remove faulthandler._sigill() and faulthandler._sigbus(): reuse
  _testcapi.raise_signal() in test_faulthandler