test: add basic tests for sendmsgtopeer to rpc_net.py

Author: mzumsande

test/functional/rpc_net.py

@@ -65,6 +65,7 @@ def run_test(self):
         self.test_service_flags()
         self.test_getnodeaddresses()
         self.test_addpeeraddress()
+        self.test_sendmsgtopeer()
 
     def test_connection_count(self):
         self.log.info("Test getconnectioncount")
@@ -328,6 +329,37 @@ def test_addpeeraddress(self):
             addrs = node.getnodeaddresses(count=0)  # getnodeaddresses re-runs the addrman checks
             assert_equal(len(addrs), 2)
 
+    def test_sendmsgtopeer(self):
+        node = self.nodes[0]
+
+        self.restart_node(0)
+        self.connect_nodes(0, 1)
+
+        self.log.info("Test sendmsgtopeer")
+        self.log.debug("Send a valid message")
+        with self.nodes[1].assert_debug_log(expected_msgs=["received: addr"]):
+            node.sendmsgtopeer(peer_id=0, msg_type="addr", msg="FFFFFF")
+
+        self.log.debug("Test error for sending to non-existing peer")
+        assert_raises_rpc_error(-1, "Error: Could not send message to peer", node.sendmsgtopeer, peer_id=100, msg_type="addr", msg="FF")
+
+        self.log.debug("Test that zero-length msg_type is allowed")
+        node.sendmsgtopeer(peer_id=0, msg_type="addr", msg="")
+
+        self.log.debug("Test error for msg_type that is too long")
+        assert_raises_rpc_error(-8, "Error: msg_type too long, max length is 12", node.sendmsgtopeer, peer_id=0, msg_type="long_msg_type", msg="FF")
+
+        self.log.debug("Test that unknown msg_type is allowed")
+        node.sendmsgtopeer(peer_id=0, msg_type="unknown", msg="FF")
+
+        self.log.debug("Test that empty msg is allowed")
+        node.sendmsgtopeer(peer_id=0, msg_type="addr", msg="FF")
+
+        self.log.debug("Test that oversized messages are allowed, but get us disconnected")
+        zero_byte_string = b'\x00' * 4000001
+        node.sendmsgtopeer(peer_id=0, msg_type="addr", msg=zero_byte_string.hex())
+        self.wait_until(lambda: len(self.nodes[0].getpeerinfo()) == 0, timeout=10)
+
 
 if __name__ == '__main__':
     NetTest().main()