As I reported on related #31761, importing autotest on Windows 10 has 3 errors with Python's shell and 4 with IDLE's, with two of those the same as the python shell failures.

IDLE can be detected in at least two ways.
>>> import sys; 'idlelib.run' in sys.modules
True
>>> type(sys.stdout).__name__ == 'PseudoOutputFile'
True

'test.autotest' in sys.modules" would detect that test.autotest is being run, whether in a Python or IDLE shell.

Running test.__main__ from an editor results in screwy behavior.  Running just 'import test.autotest' instead gives the same result.  I expected at least the latter to have the same result as when run in the shell.  Wrong.

First, there is an additional test failure.

0:00:12 [ 18/407] test_aifc
test test_aifc crashed -- Traceback (most recent call last):
  File "F:\dev\3x\lib\test\libregrtest\runtest.py", line 163, in runtest_inner
    the_module = importlib.import_module(abstest)
  File "F:\dev\3x\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 680, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "F:\dev\3x\lib\test\test_aifc.py", line 9, in <module>
    import aifc
  File "F:\dev\3x\lib\aifc.py", line 254, in <module>
    from chunk import Chunk
ImportError: cannot import name 'Chunk' from 'chunk' (F:\Python\mypy\chunk.py)

Next, the tests run normallu up to
:03:18 [ 77/407/1] test_concurrent_futures

Then, while running test_configparser, the user process crashes, IDLE restarts a new user process, and the test suite restarts (in the IDLE process?) from the beginning, sending output to the console, not IDLE, and running each test 5 times.  This all is repeatable.  The following is the initial part of the console output.

== CPython 3.7.0a1+ (heads/master:8c26a34f93, Oct 14 2017, 19:37:37) [MSC v.1900 32 bit (Intel)]
== CPython 3.7.0a1+ (heads/master:8c26a34f93, Oct 14 2017, 19:37:37) [MSC v.1900 32 bit (Intel)]
== Windows-10-10.0.14393-SP0 little-endian
== cwd: F:\dev\3x\build\test_python_2056
== CPU count: 12
== Windows-10-10.0.14393-SP0 little-endian
== CPython 3.7.0a1+ (heads/master:8c26a34f93, Oct 14 2017, 19:37:37) [MSC v.1900 32 bit (Intel)]
== cwd: F:\dev\3x\build\test_python_6020
== encodings: locale=cp1252, FS=utf-8
== CPU count: 12
== Windows-10-10.0.14393-SP0 little-endian
Run tests sequentially
== CPython 3.7.0a1+ (heads/master:8c26a34f93, Oct 14 2017, 19:37:37) [MSC v.1900 32 bit (Intel)]
== cwd: F:\dev\3x\build\test_python_272
0:00:00 [  1/407] test_grammar
== encodings: locale=cp1252, FS=utf-8
== CPU count: 12
== Windows-10-10.0.14393-SP0 little-endian
== CPython 3.7.0a1+ (heads/master:8c26a34f93, Oct 14 2017, 19:37:37) [MSC v.1900 32 bit (Intel)]
Run tests sequentially
== cwd: F:\dev\3x\build\test_python_7396
0:00:00 [  1/407] test_grammar
== Windows-10-10.0.14393-SP0 little-endian
== encodings: locale=cp1252, FS=utf-8
== CPU count: 12
== cwd: F:\dev\3x\build\test_python_13476
Run tests sequentially
== CPU count: 12
0:00:00 [  1/407] test_grammar
== encodings: locale=cp1252, FS=utf-8
== encodings: locale=cp1252, FS=utf-8
Run tests sequentially
Run tests sequentially
0:00:00 [  1/407] test_grammar
0:00:00 [  1/407] test_grammar
0:00:00 [  2/407] test_opcodes
0:00:00 [  2/407] test_opcodes
0:00:00 [  2/407] test_opcodes
0:00:00 [  2/407] test_opcodes
0:00:00 [  2/407] test_opcodes
[and so on]

I said 'crash' because the run process catches SystemExit.
>>> raise SystemExit
>>> 
I have ocassionally encountered unexpected restarts before, but never, that I remember, so easily repeatable.