[tests] Improve OpenVPN config regression test #572

- Updated u_path resolution to be independent of cwd.
- Quoted sourced path to prevent shell breakage.
- Added explicit returncode assertion for better diagnostics.
- Addressed final CodeRabbit review feedback.

Fixes #572

Author: Piyushkhobragade

tests/runtests.py

@@ -240,13 +240,15 @@ def test_create_prefix_users(self):
     def test_openvpn_config_whitespace_handling(self):
         """Verify openvpn_config_download handles whitespace."""
         import os
+        import shlex
         import subprocess
         import tempfile
 
         with tempfile.TemporaryDirectory() as tmpdir:
-            u_path = os.path.abspath("images/common/utils.sh")
+            repo_root = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+            u_path = os.path.join(repo_root, "images", "common", "utils.sh")
             script = (
-                f"source {u_path}\n"
+                f"source {shlex.quote(u_path)}\n"
                 "curl() { true; }\n"
                 "tar() { touch 'my vpn with spaces.conf'; }\n"
                 "chmod() { true; }\n"
@@ -263,6 +265,11 @@ def test_openvpn_config_whitespace_handling(self):
                 capture_output=True,
                 text=True,
             )
+            self.assertEqual(
+                res.returncode,
+                0,
+                f"Mock script failed:\nSTDOUT:\n{res.stdout}\nSTDERR:\n{res.stderr}",
+            )
             self.assertIn("PASS", res.stdout)
 
     def test_console_errors(self):