Fix `test_popen_default_stdin_stderr_and_stdin_None` when run with `-s`

testing/test_pytester.py

@@ -679,6 +679,13 @@ def test_popen_default_stdin_stderr_and_stdin_None(testdir) -> None:
     # stdout, stderr default to pipes,
     # stdin can be None to not close the pipe, avoiding
     # "ValueError: flush of closed file" with `communicate()`.
+    #
+    # Wraps the test to not make it hang when run with "-s".
+    p1 = testdir.makepyfile(
+        '''
+        import sys
+
+        def test_inner(testdir):
             p1 = testdir.makepyfile(
                 """
                 import sys
@@ -692,6 +699,10 @@ def test_popen_default_stdin_stderr_and_stdin_None(testdir) -> None:
             assert stdout.splitlines() == [b"", b"stdout"]
             assert stderr.splitlines() == [b"stderr"]
             assert proc.returncode == 0
+        '''
+    )
+    result = testdir.runpytest("-p", "pytester", str(p1))
+    assert result.ret == 0
 
 
 def test_spawn_uses_tmphome(testdir) -> None: