gh-109276: libregrtest calls random.seed() before each test (#109279)

libregrtest now calls random.seed() before running each test file
when -r/--randomize command line option is used. Moreover, it's also
called in worker processes. It should help to make tests more
deterministic. Previously, it was only called once in the main
process before running all test files and it was not called in worker
processes.

* Convert some f-strings to regular strings in test_regrtest when
  f-string is not needed.
* Remove unused all_methods variable from test_regrtest.
* Add RunTests members are now mandatory.

3 files changed, 38 insertions, 23 deletions

diff --git a/Lib/test/libregrtest/main.py b/Lib/test/libregrtest/main.py
index 2c0a6c2..f52deac 100644
--- a/Lib/test/libregrtest/main.py
+++ b/Lib/test/libregrtest/main.py
@@ -112,8 +112,11 @@ class Regrtest:
         self.junit_filename: StrPath | None = ns.xmlpath
         self.memory_limit: str | None = ns.memlimit
         self.gc_threshold: int | None = ns.threshold
-        self.use_resources: list[str] = ns.use_resources
-        self.python_cmd: list[str] | None = ns.python
+        self.use_resources: tuple[str] = tuple(ns.use_resources)
+        if ns.python:
+            self.python_cmd: tuple[str] = tuple(ns.python)
+        else:
+            self.python_cmd = None
         self.coverage: bool = ns.trace
         self.coverage_dir: StrPath | None = ns.coverdir
         self.tmp_dir: StrPath | None = ns.tempdir
@@ -377,8 +380,11 @@ class Regrtest:
         return RunTests(
             tests,
             fail_fast=self.fail_fast,
+            fail_env_changed=self.fail_env_changed,
             match_tests=self.match_tests,
             ignore_tests=self.ignore_tests,
+            match_tests_dict=None,
+            rerun=None,
             forever=self.forever,
             pgo=self.pgo,
             pgo_extended=self.pgo_extended,
@@ -393,6 +399,9 @@ class Regrtest:
             gc_threshold=self.gc_threshold,
             use_resources=self.use_resources,
             python_cmd=self.python_cmd,
+            randomize=self.randomize,
+            random_seed=self.random_seed,
+            json_fd=None,
         )
 
     def _run_tests(self, selected: TestTuple, tests: TestList | None) -> int:
diff --git a/Lib/test/libregrtest/runtests.py b/Lib/test/libregrtest/runtests.py
index 64f8f6a..656958f 100644
--- a/Lib/test/libregrtest/runtests.py
+++ b/Lib/test/libregrtest/runtests.py
@@ -16,29 +16,31 @@ class HuntRefleak:
 @dataclasses.dataclass(slots=True, frozen=True)
 class RunTests:
     tests: TestTuple
-    fail_fast: bool = False
-    fail_env_changed: bool = False
-    match_tests: FilterTuple | None = None
-    ignore_tests: FilterTuple | None = None
-    match_tests_dict: FilterDict | None = None
-    rerun: bool = False
-    forever: bool = False
-    pgo: bool = False
-    pgo_extended: bool = False
-    output_on_failure: bool = False
-    timeout: float | None = None
-    verbose: int = 0
-    quiet: bool = False
-    hunt_refleak: HuntRefleak | None = None
-    test_dir: StrPath | None = None
-    use_junit: bool = False
-    memory_limit: str | None = None
-    gc_threshold: int | None = None
-    use_resources: list[str] = dataclasses.field(default_factory=list)
-    python_cmd: list[str] | None = None
+    fail_fast: bool
+    fail_env_changed: bool
+    match_tests: FilterTuple | None
+    ignore_tests: FilterTuple | None
+    match_tests_dict: FilterDict | None
+    rerun: bool
+    forever: bool
+    pgo: bool
+    pgo_extended: bool
+    output_on_failure: bool
+    timeout: float | None
+    verbose: int
+    quiet: bool
+    hunt_refleak: HuntRefleak | None
+    test_dir: StrPath | None
+    use_junit: bool
+    memory_limit: str | None
+    gc_threshold: int | None
+    use_resources: tuple[str]
+    python_cmd: tuple[str] | None
+    randomize: bool
+    random_seed: int | None
     # On Unix, it's a file descriptor.
     # On Windows, it's a handle.
-    json_fd: int | None = None
+    json_fd: int | None
 
     def copy(self, **override):
         state = dataclasses.asdict(self)
diff --git a/Lib/test/libregrtest/setup.py b/Lib/test/libregrtest/setup.py
index 353a0f7..1c40b7c 100644
--- a/Lib/test/libregrtest/setup.py
+++ b/Lib/test/libregrtest/setup.py
@@ -1,5 +1,6 @@
 import faulthandler
 import os
+import random
 import signal
 import sys
 import unittest
@@ -127,3 +128,6 @@ def setup_tests(runtests: RunTests):
 
     if runtests.gc_threshold is not None:
         gc.set_threshold(runtests.gc_threshold)
+
+    if runtests.randomize:
+        random.seed(runtests.random_seed)