bpo-30028: improve the test case

- better comments - make sure, that the child exits successfully
gpshead · Feb 23, 2018 · Apr 9, 2017 · Apr 10, 2017 · Apr 10, 2017 · Apr 10, 2017
commit 8cebac881d4689f2f7ed8e2dfda823298d8da4f9
diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py
@@ -166,16 +166,26 @@ def test_temp_dir__existing_dir__quiet_true(self):
     @unittest.skipUnless(hasattr(os, "fork"), "test requires os.fork")
     def test_temp_dir__forked_child(self):
         """Test that a forked child process does not remove the directory."""
+        # See bpo-30028 for details.
         # Run the test as an external script, because it uses fork.
         script_helper.assert_python_ok("-c", textwrap.dedent("""
             import os
             from test import support
             with support.temp_cwd() as temp_path:
                 pid = os.fork()
                 if pid != 0:
-                    # parent process
-                    os.waitpid(pid, 0)  # wait for the child to terminate
-                    # make sure that temp_path is still present
+                    # parent process (child has pid == 0)
+
+                    # wait for the child to terminate
+                    (pid, status) = os.waitpid(pid, 0)
+                    if status != 0:
+                        raise AssertionError(f"Child process failed with exit "
+                                             f"status indication 0x{status:x}.")
+
+                    # Make sure that temp_path is still present. When the child
+                    # process leaves the 'temp_cwd'-context, the __exit__()-
+                    # method of the context must not remove the temporary
+                    # directory.
                     if not os.path.isdir(temp_path):
                         raise AssertionError("Child removed temp_path.")
         """))