| 1 | import { describe, expect, it } from "@effect/vitest"; |
| 2 | |
| 3 | import { SerializedAsyncQueue } from "./serialized-async-queue"; |
| 4 | |
| 5 | function deferred() { |
| 6 | let resolve!: () => void; |
| 7 | const promise = new Promise<void>((next) => { |
| 8 | resolve = next; |
| 9 | }); |
| 10 | return { promise, resolve }; |
| 11 | } |
| 12 | |
| 13 | describe("SerializedAsyncQueue", () => { |
| 14 | it("does not let a newer operation overtake an in-flight operation", async () => { |
| 15 | const queue = new SerializedAsyncQueue(); |
| 16 | const firstGate = deferred(); |
| 17 | const events: string[] = []; |
| 18 | |
| 19 | const first = queue.run(async () => { |
| 20 | events.push("first:start"); |
| 21 | await firstGate.promise; |
| 22 | events.push("first:end"); |
| 23 | }); |
| 24 | const second = queue.run(async () => { |
| 25 | events.push("second"); |
| 26 | }); |
| 27 | |
| 28 | await Promise.resolve(); |
| 29 | expect(events).toEqual(["first:start"]); |
| 30 | firstGate.resolve(); |
| 31 | await Promise.all([first, second]); |
| 32 | expect(events).toEqual(["first:start", "first:end", "second"]); |
| 33 | }); |
| 34 | |
| 35 | it("continues after a rejected operation", async () => { |
| 36 | const queue = new SerializedAsyncQueue(); |
| 37 | const first = queue.run(async () => { |
| 38 | throw new Error("failed"); |
| 39 | }); |
| 40 | const second = queue.run(async () => "recovered"); |
| 41 | |
| 42 | await expect(first).rejects.toThrow("failed"); |
| 43 | await expect(second).resolves.toBe("recovered"); |
| 44 | }); |
| 45 | }); |