tests: assumeutxo: accept final height from either chainstate

test/functional/feature_assumeutxo.py

@@ -159,7 +159,15 @@ class AssumeutxoTest(BitcoinTestFramework):
         self.connect_nodes(0, 1)
 
         self.log.info(f"Ensuring snapshot chain syncs to tip. ({FINAL_HEIGHT})")
-        wait_until_helper(lambda: n1.getchainstates()['snapshot']['blocks'] == FINAL_HEIGHT)
+
+        def check_for_final_height():
+            chainstates = n1.getchainstates()
+            # The background validation may have completed before we run our first
+            # check, so accept a final blockheight from either chainstate type.
+            cs = chainstates.get('snapshot') or chainstates.get('normal')
+            return cs['blocks'] == FINAL_HEIGHT
+
+        wait_until_helper(check_for_final_height)
         self.sync_blocks(nodes=(n0, n1))
 
         self.log.info("Ensuring background validation completes")