Add mutation for functional test test_preferred_inv

Add a booelan arg to test_preferred_inv to cover NONPREF_PEER_TX_DELAY
as applied as a TxRequestTracker parameter in AddTxAnnouncement.

Author: Antoine Riard

test/functional/p2p_tx_download.py

@@ -47,6 +47,7 @@ def on_getdata(self, message):
 OVERLOADED_PEER_DELAY = 2 # seconds
 MAX_GETDATA_IN_FLIGHT = 100
 MAX_PEER_TX_ANNOUNCEMENTS = 5000
+NONPREF_PEER_TX_DELAY = 2
 
 # Python test constants
 NUM_INBOUND = 10
@@ -207,14 +208,24 @@ def test_notfound_fallback(self):
         with p2p_lock:
             assert_equal(peer_fallback.tx_getdata_count, 1)
 
-    def test_preferred_inv(self):
-        self.log.info('Check that invs from preferred peers are downloaded immediately')
-        self.restart_node(0, extra_args=['[email protected]'])
+    def test_preferred_inv(self, preferred=False):
+        if preferred:
+            self.log.info('Check invs from preferred peers are downloaded immediately')
+            self.restart_node(0, extra_args=['[email protected]'])
+        else:
+            self.log.info('Check invs from non-preferred peers are downloaded after {} s'.format(NONPREF_PEER_TX_DELAY))
+        mock_time = int(time.time() + 1)
+        self.nodes[0].setmocktime(mock_time)
         peer = self.nodes[0].add_p2p_connection(TestP2PConn())
         peer.send_message(msg_inv([CInv(t=MSG_WTX, h=0xff00ff00)]))
-        peer.wait_until(lambda: peer.tx_getdata_count >= 1, timeout=1)
-        with p2p_lock:
-            assert_equal(peer.tx_getdata_count, 1)
+        peer.sync_with_ping()
+        if preferred:
+            peer.wait_until(lambda: peer.tx_getdata_count >= 1, timeout=1)
+        else:
+            with p2p_lock:
+                assert_equal(peer.tx_getdata_count, 0)
+            self.nodes[0].setmocktime(mock_time + NONPREF_PEER_TX_DELAY)
+            peer.wait_until(lambda: peer.tx_getdata_count >= 1, timeout=1)
 
     def test_txid_inv_delay(self, glob_wtxid=False):
         self.log.info('Check that inv from a txid-relay peers are delayed by {} s, with a wtxid peer {}'.format(TXID_RELAY_DELAY, glob_wtxid))
@@ -261,6 +272,7 @@ def run_test(self):
         self.test_disconnect_fallback()
         self.test_notfound_fallback()
         self.test_preferred_inv()
+        self.test_preferred_inv(True)
         self.test_txid_inv_delay()
         self.test_txid_inv_delay(True)
         self.test_large_inv_batch()