Reload map on reconnect (#8848)

PSD-282

test/utils/connection-test.ts

@@ -0,0 +1,52 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { ClientEvent, ClientEventHandlerMap } from "matrix-js-sdk/src/matrix";
+import { SyncState } from "matrix-js-sdk/src/sync";
+
+import { createReconnectedListener } from "../../src/utils/connection";
+
+describe("createReconnectedListener", () => {
+    let reconnectedListener: ClientEventHandlerMap[ClientEvent.Sync];
+    let onReconnect: jest.Mock;
+
+    beforeEach(() => {
+        onReconnect = jest.fn();
+        reconnectedListener = createReconnectedListener(onReconnect);
+    });
+
+    [
+        [SyncState.Prepared, SyncState.Syncing],
+        [SyncState.Syncing, SyncState.Reconnecting],
+        [SyncState.Reconnecting, SyncState.Syncing],
+    ].forEach(([from, to]) => {
+        it(`should invoke the callback on a transition from ${from} to ${to}`, () => {
+            reconnectedListener(to, from);
+            expect(onReconnect).toBeCalled();
+        });
+    });
+
+    [
+        [SyncState.Syncing, SyncState.Syncing],
+        [SyncState.Catchup, SyncState.Error],
+        [SyncState.Reconnecting, SyncState.Error],
+    ].forEach(([from, to]) => {
+        it(`should not invoke the callback on a transition from ${from} to ${to}`, () => {
+            reconnectedListener(to, from);
+            expect(onReconnect).not.toBeCalled();
+        });
+    });
+});