Add an alternative method to check block graph, to be used in further
commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 tests/qemu-iotests/iotests.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index ea48af4a7b..8a5fd01eac 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -1108,6 +1108,23 @@ def check_bitmap_status(self, node_name, bitmap_name, fields):
 
         return fields.items() <= ret.items()
 
+    def get_block_graph(self):
+        """
+        Returns block graph in form of edges list, where each edge is a tuple:
+          (parent_node_name, child_name, child_node_name)
+        """
+        graph = self.qmp('x-debug-query-block-graph')['return']
+
+        nodes = {n['id']: n['name'] for n in graph['nodes']}
+        # Check that all names are unique:
+        assert len(set(nodes.values())) == len(nodes)
+
+        return [(nodes[e['parent']], e['name'], nodes[e['child']])
+                for e in graph['edges']]
+
+    def assert_edges_list(self, edges):
+        assert sorted(edges) == sorted(self.get_block_graph())
+
     def assert_block_path(self, root, path, expected_node, graph=None):
         """
         Check whether the node under the given path in the block graph
-- 
2.34.1