qemu-iotests: allow valgrind to read/delete the generated log file

When using -valgrind on the script tests, it generates a log file
in $TEST_DIR that is either read (if valgrind finds problems) or
otherwise deleted. Provide the same exact behavior when using
-valgrind on the python tests.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210809090114.64834-13-eesposit@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

tests/qemu-iotests/iotests.py

@@ -598,6 +598,17 @@ def __init__(self, path_suffix=''):
                          sock_dir=sock_dir, qmp_timer=timer)
         self._num_drives = 0
 
+    def _post_shutdown(self) -> None:
+        super()._post_shutdown()
+        if not qemu_valgrind or not self._popen:
+            return
+        valgrind_filename =  f"{test_dir}/{self._popen.pid}.valgrind"
+        if self.exitcode() == 99:
+            with open(valgrind_filename) as f:
+                print(f.read())
+        else:
+            os.remove(valgrind_filename)
+
     def add_object(self, opts):
         self._args.append('-object')
         self._args.append(opts)