test: use wait_until for invs matching in p2p_feefilter.py

additionally:
    -> rename function with snake_case (s/allInvsMatch/wait_for_invs_to_match)
    -> move it from global namespace to the class FeefilterConn

test/functional/p2p_feefilter.py

@@ -5,7 +5,6 @@
 """Test processing of feefilter messages."""
 
 from decimal import Decimal
-import time
 
 from test_framework.messages import MSG_TX, MSG_WTX, msg_feefilter
 from test_framework.mininode import mininode_lock, P2PInterface
@@ -17,16 +16,6 @@ def hashToHex(hash):
     return format(hash, '064x')
 
 
-# Wait up to 60 secs to see if the testnode has received all the expected invs
-def allInvsMatch(invsExpected, testnode):
-    for _ in range(60):
-        with mininode_lock:
-            if (sorted(invsExpected) == sorted(testnode.txinvs)):
-                return True
-        time.sleep(1)
-    return False
-
-
 class FeefilterConn(P2PInterface):
     feefilter_received = False
 
@@ -48,6 +37,10 @@ class TestP2PConn(P2PInterface):
             if (i.type == MSG_TX) or (i.type == MSG_WTX):
                 self.txinvs.append(hashToHex(i.hash))
 
+    def wait_for_invs_to_match(self, invs_expected):
+        invs_expected.sort()
+        self.wait_until(lambda: invs_expected == sorted(self.txinvs), timeout=60)
+
     def clear_invs(self):
         with mininode_lock:
             self.txinvs = []
@@ -91,7 +84,7 @@ class FeeFilterTest(BitcoinTestFramework):
         self.log.info("Test txs paying 0.2 sat/byte are received by test connection")
         node1.settxfee(Decimal("0.00000200"))
         txids = [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
-        assert allInvsMatch(txids, conn)
+        conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 
         # Set a fee filter of 0.15 sat/byte on test connection
@@ -100,7 +93,7 @@ class FeeFilterTest(BitcoinTestFramework):
         self.log.info("Test txs paying 0.15 sat/byte are received by test connection")
         node1.settxfee(Decimal("0.00000150"))
         txids = [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
-        assert allInvsMatch(txids, conn)
+        conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 
         self.log.info("Test txs paying 0.1 sat/byte are no longer received by test connection")
@@ -117,13 +110,13 @@ class FeeFilterTest(BitcoinTestFramework):
         # as well.
         node0.settxfee(Decimal("0.00020000"))
         txids = [node0.sendtoaddress(node0.getnewaddress(), 1)]
-        assert allInvsMatch(txids, conn)
+        conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 
         self.log.info("Remove fee filter and check txs are received again")
         conn.send_and_ping(msg_feefilter(0))
         txids = [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
-        assert allInvsMatch(txids, conn)
+        conn.wait_for_invs_to_match(txids)
         conn.clear_invs()