bpo-36725: regrtest: add TestResult type (GH-12960)

* Add TestResult and MultiprocessResult types to ensure that results
  always have the same fields.
* runtest() now handles KeyboardInterrupt
* accumulate_result() and format_test_result() now takes a TestResult
* cleanup_test_droppings() is now called by runtest() and mark the
  test as ENV_CHANGED if the test leaks support.TESTFN file.
* runtest() now includes code "around" the test in the test timing
* Add print_warning() in test.libregrtest.utils to standardize how
  libregrtest logs warnings to ease parsing the test output.
* support.unload() is now called with abstest rather than test_name
* Rename 'test' variable/parameter to 'test_name'
* dash_R(): remove unused the_module parameter
* Remove unused imports

1 files changed, 15 insertions, 13 deletions

diff --git a/Lib/test/test_regrtest.py b/Lib/test/test_regrtest.py
index a9febd0..5c65e6d 100644
--- a/Lib/test/test_regrtest.py
+++ b/Lib/test/test_regrtest.py
@@ -26,8 +26,9 @@ ROOT_DIR = os.path.join(os.path.dirname(__file__), '..', '..')
 ROOT_DIR = os.path.abspath(os.path.normpath(ROOT_DIR))
 
 TEST_INTERRUPTED = textwrap.dedent("""
-    from signal import SIGINT, raise_signal
+    from signal import SIGINT
     try:
+        from signal import raise_signal
         raise_signal(SIGINT)
     except ImportError:
         import os
@@ -108,7 +109,7 @@ class ParseArgsTestCase(unittest.TestCase):
                 self.assertTrue(ns.quiet)
                 self.assertEqual(ns.verbose, 0)
 
-    def test_slow(self):
+    def test_slowest(self):
         for opt in '-o', '--slowest':
             with self.subTest(opt=opt):
                 ns = libregrtest._parse_args([opt])
@@ -780,22 +781,23 @@ class ArgsTestCase(BaseTestCase):
                  % (self.TESTNAME_REGEX, len(tests)))
         self.check_line(output, regex)
 
-    def test_slow_interrupted(self):
+    def test_slowest_interrupted(self):
         # Issue #25373: test --slowest with an interrupted test
         code = TEST_INTERRUPTED
         test = self.create_test("sigint", code=code)
 
         for multiprocessing in (False, True):
-            if multiprocessing:
-                args = ("--slowest", "-j2", test)
-            else:
-                args = ("--slowest", test)
-            output = self.run_tests(*args, exitcode=130)
-            self.check_executed_tests(output, test,
-                                      omitted=test, interrupted=True)
-
-            regex = ('10 slowest tests:\n')
-            self.check_line(output, regex)
+            with self.subTest(multiprocessing=multiprocessing):
+                if multiprocessing:
+                    args = ("--slowest", "-j2", test)
+                else:
+                    args = ("--slowest", test)
+                output = self.run_tests(*args, exitcode=130)
+                self.check_executed_tests(output, test,
+                                          omitted=test, interrupted=True)
+
+                regex = ('10 slowest tests:\n')
+                self.check_line(output, regex)
 
     def test_coverage(self):
         # test --coverage