gh-121359: Run test_pyrepl in isolated mode (#121414)

run_repl() now pass the -I option (isolated mode) to Python if the
'env' parameter is not set.

diff --git a/Lib/test/test_pyrepl/test_pyrepl.py b/Lib/test/test_pyrepl/test_pyrepl.py
index 93c80467a04546b80424ace066739b69af1e6134..7621b8af808f532808272a43e0e6f6abe5c8e538 100644 (file)
--- a/Lib/test/test_pyrepl/test_pyrepl.py
+++ b/Lib/test/test_pyrepl/test_pyrepl.py
@@ -927,8 +927,11 @@ class TestMain(TestCase):
 
     def run_repl(self, repl_input: str | list[str], env: dict | None = None) -> tuple[str, int]:
         master_fd, slave_fd = pty.openpty()
+        cmd = [sys.executable, "-i", "-u"]
+        if env is None:
+            cmd.append("-I")
         process = subprocess.Popen(
-            [sys.executable, "-i", "-u"],
+            cmd,
             stdin=slave_fd,
             stdout=slave_fd,
             stderr=slave_fd,