[tests] Remove rpc_zmq.py

rpc_zmq.py is racy and fails intermittently. Remove that test file and
move the getzmqnotifications RPC test into interface_zmq.py

Author: jnewbery

test/functional/interface_zmq.py

@@ -14,6 +14,7 @@
 )
 from io import BytesIO
 
+ADDRESS = "tcp://127.0.0.1:28332"
 
 class ZMQSubscriber:
     def __init__(self, socket, topic):
@@ -51,11 +52,10 @@ def setup_nodes(self):
         # that this test fails if the publishing order changes.
         # Note that the publishing order is not defined in the documentation and
         # is subject to change.
-        address = "tcp://127.0.0.1:28332"
         self.zmq_context = zmq.Context()
         socket = self.zmq_context.socket(zmq.SUB)
         socket.set(zmq.RCVTIMEO, 60000)
-        socket.connect(address)
+        socket.connect(ADDRESS)
 
         # Subscribe to all available topics.
         self.hashblock = ZMQSubscriber(socket, b"hashblock")
@@ -64,7 +64,7 @@ def setup_nodes(self):
         self.rawtx = ZMQSubscriber(socket, b"rawtx")
 
         self.extra_args = [
-            ["-zmqpub%s=%s" % (sub.topic.decode(), address) for sub in [self.hashblock, self.hashtx, self.rawblock, self.rawtx]],
+            ["-zmqpub%s=%s" % (sub.topic.decode(), ADDRESS) for sub in [self.hashblock, self.hashtx, self.rawblock, self.rawtx]],
             [],
         ]
         self.add_nodes(self.num_nodes, self.extra_args)
@@ -117,5 +117,15 @@ def _zmq_test(self):
         hex = self.rawtx.receive()
         assert_equal(payment_txid, bytes_to_hex_str(hash256(hex)))
 
+        self.log.info("Test the getzmqnotifications RPC")
+        assert_equal(self.nodes[0].getzmqnotifications(), [
+            {"type": "pubhashblock", "address": ADDRESS},
+            {"type": "pubhashtx", "address": ADDRESS},
+            {"type": "pubrawblock", "address": ADDRESS},
+            {"type": "pubrawtx", "address": ADDRESS},
+        ])
+
+        assert_equal(self.nodes[1].getzmqnotifications(), [])
+
 if __name__ == '__main__':
     ZMQTest().main()

test/functional/rpc_zmq.py

@@ -152,7 +152,6 @@
     'feature_versionbits_warning.py',
     'rpc_preciousblock.py',
     'wallet_importprunedfunds.py',
-    'rpc_zmq.py',
     'rpc_signmessage.py',
     'feature_nulldummy.py',
     'mempool_accept.py',