Add a filter function for QMP responses that contain QEMU's
automatically generated node ids. The ids change between runs and must
be masked in the reference output.

The next commit will use this new function.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/qemu-iotests/iotests.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index e5c5798c71..ea48af4a7b 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -651,6 +651,13 @@ def _filter(_key, value):
 def filter_generated_node_ids(msg):
     return re.sub("#block[0-9]+", "NODE_NAME", msg)
 
+def filter_qmp_generated_node_ids(qmsg):
+    def _filter(_key, value):
+        if is_str(value):
+            return filter_generated_node_ids(value)
+        return value
+    return filter_qmp(qmsg, _filter)
+
 def filter_img_info(output: str, filename: str,
                     drop_child_info: bool = True) -> str:
     lines = []
-- 
2.43.0