bpo-33873: Backport regrtest from master to 3.7 (GH-7935) (GH-7937)

* bpo-33718: regrtest: use format_duration() to display failed tests (GH-7686)

* Enhance also format_duration(): work on integers and rounds towards
  +infinity (math.ceil).
* Write unit tests on format_duration()

(cherry picked from commit 4ffe9c2b251f6e027b26250b7a2618e78d4edd22)

* bpo-33873: regrtest: Add warning on -R 1:3 (GH-7736)

regrtest: Add warning when using less than 3 warmup runs like -R 1:3.
(cherry picked from commit cac4fef8860e66a9da67d09762f5b614b9471a12)

* bpo-33873: Fix bug in `runtest.py` and add checks for invalid `-R` parameters (GH-7735)

Fix bug in `Lib/test/libregrtest/runtest.py` that makes running tests an extra time than the specified number of runs.

Add check for invalid --huntrleaks/-R parameters.

(cherry picked from commit 58ed7307ea0b5c5aa052291ebc3030f314f938d8)
(cherry picked from commit d1f9481b7a2d31c40fca1347ef99d819eb656ce7)

1 files changed, 16 insertions, 0 deletions

diff --git a/Lib/test/libregrtest/main.py b/Lib/test/libregrtest/main.py
index 3429b3726a..e262a7a172 100644
--- a/Lib/test/libregrtest/main.py
+++ b/Lib/test/libregrtest/main.py
@@ -462,6 +462,13 @@ class Regrtest:
                    or self.tests or self.ns.args)):
             self.display_header()
 
+        if self.ns.huntrleaks:
+            warmup, repetitions, _ = self.ns.huntrleaks
+            if warmup < 3:
+                msg = ("WARNING: Running tests with --huntrleaks/-R and less than "
+                        "3 warmup repetitions can give false positives!")
+                print(msg, file=sys.stdout, flush=True)
+
         if self.ns.randomize:
             print("Using random seed", self.ns.random_seed)
 
@@ -526,6 +533,15 @@ class Regrtest:
     def _main(self, tests, kwargs):
         self.ns = self.parse_args(kwargs)
 
+        if self.ns.huntrleaks:
+            warmup, repetitions, _ = self.ns.huntrleaks
+            if warmup < 1 or repetitions < 1:
+                msg = ("Invalid values for the --huntrleaks/-R parameters. The "
+                       "number of warmups and repetitions must be at least 1 "
+                       "each (1:1).")
+                print(msg, file=sys.stderr, flush=True)
+                sys.exit(2)
+
         if self.ns.slaveargs is not None:
             from test.libregrtest.runtest_mp import run_tests_slave
             run_tests_slave(self.ns.slaveargs)