diff --git a/tests/unit/test_connection.py b/tests/unit/test_connection.py
new file mode 100644
index 0000000..f69b8d6
--- /dev/null
+++ b/tests/unit/test_connection.py
@@ -0,0 +1,54 @@
+import asyncio
+import json
+import mock
+import pytest
+from collections import deque
+
+from websockets.exceptions import ConnectionClosed
+
+from .. import base
+from juju.client.connection import Connection
+
+
+class WebsocketMock:
+    def __init__(self, responses):
+        super().__init__()
+        self.responses = deque(responses)
+        self.open = True
+
+    async def send(self, message):
+        pass
+
+    async def recv(self):
+        if not self.responses:
+            await asyncio.sleep(1)  # delay to give test time to finish
+            raise ConnectionClosed(0, 'ran out of responses')
+        return json.dumps(self.responses.popleft())
+
+    async def close(self):
+        self.open = False
+
+
+@pytest.mark.asyncio
+async def test_out_of_order(event_loop):
+    con = Connection(*[None]*4)
+    ws = WebsocketMock([
+        {'request-id': 1},
+        {'request-id': 3},
+        {'request-id': 2},
+    ])
+    expected_responses = [
+        {'request-id': 1},
+        {'request-id': 2},
+        {'request-id': 3},
+    ]
+    con._get_sll = mock.MagicMock()
+    try:
+        with mock.patch('websockets.connect', base.AsyncMock(return_value=ws)):
+            await con.open()
+        actual_responses = []
+        for i in range(3):
+            actual_responses.append(await con.rpc({'version': 1}))
+        assert actual_responses == expected_responses
+    finally:
+        await con.close()