diff --git a/test/functional/feature_assumevalid.py b/test/functional/feature_assumevalid.py
index 0ef0b619f2..f8c6a90945 100755
--- a/test/functional/feature_assumevalid.py
+++ b/test/functional/feature_assumevalid.py
@@ -29,9 +29,12 @@ Start three nodes:
       block 200. node2 will reject block 102 since it's assumed valid, but it
       isn't buried by at least two weeks' work.
 """
-import time
 
-from test_framework.blocktools import (COINBASE_MATURITY,create_block, create_coinbase)
+from test_framework.blocktools import (
+    COINBASE_MATURITY,
+    create_block,
+    create_coinbase,
+)
 from test_framework.key import ECKey
 from test_framework.messages import (
     CBlockHeader,
@@ -45,7 +48,7 @@ from test_framework.messages import (
 from test_framework.mininode import P2PInterface
 from test_framework.script import (CScript, OP_TRUE)
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import (assert_equal, set_node_times)
+from test_framework.util import (assert_equal, set_node_times, wait_until)
 
 
 class BaseNode(P2PInterface):
@@ -80,24 +83,6 @@ class AssumeValidTest(BitcoinTestFramework):
                 assert not p2p_conn.is_connected
                 break
 
-    def assert_blockchain_height(self, node, height):
-        """Wait until the blockchain is no longer advancing and verify it's reached the expected height."""
-        last_height = node.getblock(node.getbestblockhash())['height']
-        timeout = 10
-        while True:
-            time.sleep(0.25)
-            current_height = node.getblock(node.getbestblockhash())['height']
-            if current_height != last_height:
-                last_height = current_height
-                if timeout < 0:
-                    assert False, "blockchain too short after timeout: %d" % current_height
-                timeout -= 0.25
-                continue
-            elif current_height > height:
-                assert False, "blockchain too long: %d" % current_height
-            elif current_height == height:
-                break
-
     def run_test(self):
         p2p0 = self.nodes[0].add_p2p_connection(BaseNode())
 
@@ -187,7 +172,8 @@ class AssumeValidTest(BitcoinTestFramework):
 
         # Send blocks to node0. Block 102 will be rejected.
         self.send_blocks_until_disconnected(p2p0)
-        self.assert_blockchain_height(self.nodes[0], COINBASE_MATURITY + 1)
+        wait_until(lambda: self.nodes[0].getblockcount() >= COINBASE_MATURITY + 1)
+        assert_equal(self.nodes[0].getblockcount(), COINBASE_MATURITY + 1)
 
         # Send 200 blocks to node1. All blocks, including block 102, will be accepted.
         for i in range(200):
@@ -198,7 +184,8 @@ class AssumeValidTest(BitcoinTestFramework):
 
         # Send blocks to node2. Block 102 will be rejected.
         self.send_blocks_until_disconnected(p2p2)
-        self.assert_blockchain_height(self.nodes[2], COINBASE_MATURITY + 1)
+        wait_until(lambda: self.nodes[2].getblockcount() >= COINBASE_MATURITY + 1)
+        assert_equal(self.nodes[2].getblockcount(), COINBASE_MATURITY + 1)
 
 
 if __name__ == '__main__':