test: Fix intermittent issue in mining_getblocktemplate_longpoll.py

test/functional/mining_getblocktemplate_longpoll.py

@@ -41,6 +41,7 @@ class GetBlockTemplateLPTest(BitcoinTestFramework):
 
         self.log.info("Test that longpoll waits if we do nothing")
         thr = LongpollThread(self.nodes[0])
+        with self.nodes[0].assert_debug_log(["ThreadRPCServer method=getblocktemplate"], timeout=3):
             thr.start()
         # check that thread still lives
         thr.join(5)  # wait 5 seconds or until thread exits
@@ -55,6 +56,7 @@ class GetBlockTemplateLPTest(BitcoinTestFramework):
 
         self.log.info("Test that longpoll will terminate if we generate a block ourselves")
         thr = LongpollThread(self.nodes[0])
+        with self.nodes[0].assert_debug_log(["ThreadRPCServer method=getblocktemplate"], timeout=3):
             thr.start()
         self.generate(self.nodes[0], 1)  # generate a block on own node
         thr.join(5)  # wait 5 seconds or until thread exits
@@ -62,6 +64,7 @@ class GetBlockTemplateLPTest(BitcoinTestFramework):
 
         self.log.info("Test that introducing a new transaction into the mempool will terminate the longpoll")
         thr = LongpollThread(self.nodes[0])
+        with self.nodes[0].assert_debug_log(["ThreadRPCServer method=getblocktemplate"], timeout=3):
             thr.start()
         # generate a transaction and submit it
         self.miniwallet.send_self_transfer(from_node=random.choice(self.nodes))