import { beforeEach, describe, expect, it, vi } from "vitest";
import { fetchWithRateLimit } from "../src/utils.js";
function makeHeaders(init?: Record<string, string>) {
return new Headers(init);
}
function makeFetchResponse(opts: {
status: number;
headers?: Record<string, string>;
}): Pick<Response, "status" | "headers"> {
return {
status: opts.status,
headers: makeHeaders(opts.headers),
};
}
describe("fetchWithRateLimit", () => {
beforeEach(() => {
vi.useFakeTimers();
vi.spyOn(console, "error").mockImplementation(() => {});
});
it("waits a small courtesy delay before calling fetch", async () => {
const fetchSpy = vi
.fn()
.mockResolvedValue(makeFetchResponse({ status: 200 }) as Response);
vi.stubGlobal("fetch", fetchSpy);
const p = fetchWithRateLimit("https://example.com", { method: "GET" });
expect(fetchSpy).not.toHaveBeenCalled();
// MIN_DELAY_MS in src/utils.ts is 50ms
await vi.advanceTimersByTimeAsync(50);
await p;
expect(fetchSpy).toHaveBeenCalledTimes(1);
});
it("retries on 429 using RateLimit-Reset header", async () => {
const fetchSpy = vi
.fn()
.mockResolvedValueOnce(
makeFetchResponse({
status: 429,
headers: { "RateLimit-Reset": "2" },
}) as Response
)
.mockResolvedValueOnce(makeFetchResponse({ status: 200 }) as Response);
vi.stubGlobal("fetch", fetchSpy);
const p = fetchWithRateLimit("https://example.com", { method: "GET" }, 1);
// First delay (50ms) + rate limit wait (2s) + second delay (50ms)
await vi.advanceTimersByTimeAsync(50);
expect(fetchSpy).toHaveBeenCalledTimes(1);
await vi.advanceTimersByTimeAsync(2000);
await vi.advanceTimersByTimeAsync(50);
const res = await p;
expect(res.status).toBe(200);
expect(fetchSpy).toHaveBeenCalledTimes(2);
});
it("stops retrying when retries reach 0 and returns the 429 response", async () => {
const fetchSpy = vi
.fn()
.mockResolvedValue(
makeFetchResponse({
status: 429,
headers: { "RateLimit-Reset": "1" },
}) as Response
);
vi.stubGlobal("fetch", fetchSpy);
const p = fetchWithRateLimit("https://example.com", { method: "GET" }, 0);
await vi.advanceTimersByTimeAsync(50);
const res = await p;
expect(res.status).toBe(429);
expect(fetchSpy).toHaveBeenCalledTimes(1);
});
});
