Offload some more waveform processing onto a worker (#9223)

test/WorkerManager-test.ts

@@ -0,0 +1,59 @@
+/*
+Copyright 2023 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 { WorkerManager } from "../src/WorkerManager";
+
+describe("WorkerManager", () => {
+    it("should generate consecutive sequence numbers for each call", () => {
+        const postMessage = jest.fn();
+        const manager = new WorkerManager(jest.fn(() => ({ postMessage } as unknown as Worker)));
+
+        manager.call({ data: "One" });
+        manager.call({ data: "Two" });
+        manager.call({ data: "Three" });
+
+        const one = postMessage.mock.calls.find((c) => c[0].data === "One")!;
+        const two = postMessage.mock.calls.find((c) => c[0].data === "Two")!;
+        const three = postMessage.mock.calls.find((c) => c[0].data === "Three")!;
+
+        expect(one[0].seq).toBe(0);
+        expect(two[0].seq).toBe(1);
+        expect(three[0].seq).toBe(2);
+    });
+
+    it("should support resolving out of order", async () => {
+        const postMessage = jest.fn();
+        const worker = { postMessage } as unknown as Worker;
+        const manager = new WorkerManager(jest.fn(() => worker));
+
+        const oneProm = manager.call({ data: "One" });
+        const twoProm = manager.call({ data: "Two" });
+        const threeProm = manager.call({ data: "Three" });
+
+        const one = postMessage.mock.calls.find((c) => c[0].data === "One")![0].seq;
+        const two = postMessage.mock.calls.find((c) => c[0].data === "Two")![0].seq;
+        const three = postMessage.mock.calls.find((c) => c[0].data === "Three")![0].seq;
+
+        worker.onmessage!({ data: { seq: one, data: 1 } } as MessageEvent);
+        await expect(oneProm).resolves.toEqual(expect.objectContaining({ data: 1 }));
+
+        worker.onmessage!({ data: { seq: three, data: 3 } } as MessageEvent);
+        await expect(threeProm).resolves.toEqual(expect.objectContaining({ data: 3 }));
+
+        worker.onmessage!({ data: { seq: two, data: 2 } } as MessageEvent);
+        await expect(twoProm).resolves.toEqual(expect.objectContaining({ data: 2 }));
+    });
+});