tests: fix default failed dir setting

When running tests via run.sh, default setting of None would cause
failed directory symlink to appear in vpp workspace with an ugly name.
This patch places the symlink in temporary directory.

Type: fix
Fixes: b23ffd7ef2
Signed-off-by: Klement Sekera <klement.sekera@gmail.com>
Change-Id: Ic1715eba7ac1f82f71855e2aeb9b659d27bbb3af

test/config.py

@@ -1,7 +1,6 @@
 import argparse
 import os
 import psutil
-import textwrap
 import time
 
 
@@ -119,7 +118,7 @@ parser.add_argument(
     "--failed-dir",
     action="store",
     type=directory,
-    help="directory containing failed tests",
+    help="directory containing failed tests (default: --tmp-dir)",
 )
 
 filter_help_string = """\
@@ -357,8 +356,7 @@ parser.add_argument(
     "--keep-pcaps",
     action="store_true",
     default=default_keep_pcaps,
-    help="if set, keep all pcap files from a test run"
-    f" (default: {default_keep_pcaps})",
+    help=f"if set, keep all pcap files from a test run (default: {default_keep_pcaps})",
 )
 
 config = parser.parse_args()
@@ -399,6 +397,9 @@ config.test_src_dir = test_dirs
 if config.venv_dir is None:
     config.venv_dir = f"{ws}/test/venv"
 
+if config.failed_dir is None:
+    config.failed_dir = f"{config.tmp_dir}"
+
 available_cpus = psutil.Process().cpu_affinity()
 num_cpus = len(available_cpus)