diff --git a/test/mitmproxy/tools/web/test_app.py b/test/mitmproxy/tools/web/test_app.py
index e251c6026..70b27154f 100644
--- a/test/mitmproxy/tools/web/test_app.py
+++ b/test/mitmproxy/tools/web/test_app.py
@@ -244,6 +244,13 @@ class TestApp(tornado.testing.AsyncHTTPTestCase):
         assert f.response.headers["bar"] == "baz"
         assert f.response.text == "resp"
 
+        upd = {
+            "request": {"trailers": [("foo", "baz")], },
+            "response": {"trailers": [("foo", "baz")], },
+        }
+        assert self.put_json("/flows/42", upd).code == 200
+        assert f.request.trailers["foo"] == "baz"
+
         f.revert()
 
         assert self.put_json("/flows/42", {"foo": 42}).code == 400
@@ -257,13 +264,6 @@ class TestApp(tornado.testing.AsyncHTTPTestCase):
             body="!!"
         ).code == 400
 
-        upd = {
-            "request": {"trailers": [("foo", "baz")],},
-            "response": {"trailers": [("foo", "baz")],},
-        }
-        assert self.put_json("/flows/42", upd).code == 200
-        assert f.request.trailers["foo"] == "baz"
-
     def test_flow_duplicate(self):
         resp = self.fetch("/flows/42/duplicate", method="POST")
         assert resp.code == 200
diff --git a/web/src/js/__tests__/backends/websocketSpec.tsx b/web/src/js/__tests__/backends/websocketSpec.tsx
index aedc80c63..a8a416338 100644
--- a/web/src/js/__tests__/backends/websocketSpec.tsx
+++ b/web/src/js/__tests__/backends/websocketSpec.tsx
@@ -49,7 +49,17 @@ test("websocket backend", async () => {
         {type: "EVENTS_RECEIVE", cmd: "receive", data: [], resource: "events"},
         connectionActions.connectionEstablished(),
     ]))
+    store.clearActions()
     expect(fetchMock.mock.calls).toHaveLength(4);
 
+    console.error = jest.fn();
+    backend.onClose(new CloseEvent("Connection closed"));
+    expect(console.error).toBeCalledTimes(1);
+    expect(store.getActions()[0].type).toEqual(connectionActions.ConnectionState.ERROR);
+    store.clearActions();
+
+    backend.onError(null);
+    expect(console.error).toBeCalledTimes(2);
+
     jest.restoreAllMocks();
 });