functional: always enable all python warnings

Of most importance is that this gives us a heads-up if anything
we rely on has been deprecated. The default python behaviour
only emits a warning if triggered from __main__ which is very
limited.

Setting the env variable further ensures that any python child
processes will also display warnings.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250715143023.1851000-11-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/functional/qemu_test/testcase.py

@@ -19,6 +19,7 @@ import shutil
 from subprocess import run
 import sys
 import tempfile
+import warnings
 import unittest
 import uuid
 
@@ -235,6 +236,9 @@ class QemuBaseTest(unittest.TestCase):
         self._log_fh.close()
 
     def main():
+        warnings.simplefilter("default")
+        os.environ["PYTHONWARNINGS"] = "default"
+
         path = os.path.basename(sys.argv[0])[:-3]
 
         cache = os.environ.get("QEMU_TEST_PRECACHE", None)