Fix the test

jest.setup.ts

@@ -9,10 +9,10 @@ declare global {
       ): R;
     }
     interface Expect {
-      matchesPredicate(predicate: (actual: any) => boolean): any
+      matchesPredicate(predicate: (actual: any) => boolean): any;
     }
     interface ExpectExtendMap {
-      matchesPredicate: MatcherFunction<[predicate: (actual: any) => boolean]>
+      matchesPredicate: MatcherFunction<[predicate: (actual: any) => boolean]>;
     }
   }
 }
@@ -67,6 +67,7 @@ But instead it was:
       message: () => "Expected function to throw but it did not",
     };
   },
+
   matchesPredicate(actual: any, predicate: (actual: any) => boolean) {
     return {
       pass: predicate(actual),

src/domain/release-archive.spec.ts

@@ -5,6 +5,7 @@ import fs, { WriteStream } from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import tar from "tar";
+import "../../jest.setup";
 import { fakeModuleFile } from "../test/mock-template-files";
 import { expectThrownError } from "../test/util";
 import {
@@ -66,16 +67,22 @@ describe("fetch", () => {
   });
 
   test("retries the request if it fails", async () => {
+    // Restore the original behavior of exponentialDelay.
+    mocked(axiosRetry.exponentialDelay).mockImplementation(
+      jest.requireActual("axios-retry").exponentialDelay
+    );
+
     await ReleaseArchive.fetch(RELEASE_ARCHIVE_URL, STRIP_PREFIX);
 
     expect(axiosRetry).toHaveBeenCalledWith(axios, {
       retries: 3,
       retryDelay: expect.matchesPredicate((retryDelayFn: Function) => {
         // Make sure the retry delays follow exponential backoff
         // and the final retry happens after at least 1 minute total.
-        let firstRetryDelay = retryDelayFn(0);
-        let secondRetryDelay = retryDelayFn(1);
-        let thirdRetryDelay = retryDelayFn(2);
+        // Axios also randomly adds up to 20% to each delay, so test the upper bounds as well.
+        let firstRetryDelay = retryDelayFn.call(this, 0);
+        let secondRetryDelay = retryDelayFn.call(this, 1);
+        let thirdRetryDelay = retryDelayFn.call(this, 2);
         return 10000 <= firstRetryDelay && firstRetryDelay <= 12000
           && 20000 <= secondRetryDelay && secondRetryDelay <= 24000
           && 40000 <= thirdRetryDelay && thirdRetryDelay <= 48000;

src/domain/release-archive.ts

@@ -108,11 +108,12 @@ export class ReleaseArchive {
   }
 }
 
-function exponentialDelay(retryCount: number, error: AxiosError = undefined): number {
-    // Using exponential backoff with 3 retries and a delay factor of 10 seconds
-    // gives you at least 70 seconds to publish a release archive.
-    const tenSeconds = 10000;
-    return axiosRetry.exponentialDelay(retryCount, error, tenSeconds);
+function tenSecondExponentialDelay(
+  retryCount: number,
+  error: AxiosError | undefined
+): number {
+  const tenSeconds = 10000;
+  return axiosRetry.exponentialDelay(retryCount, error, tenSeconds);
 }
 
 async function download(url: string, dest: string): Promise<void> {
@@ -131,10 +132,12 @@ async function download(url: string, dest: string): Promise<void> {
 
   const writer = fs.createWriteStream(dest, { flags: "w" });
 
-  // Retry the request in case the artifact is still being uploaded
+  // Retry the request in case the artifact is still being uploaded.
+  // Exponential backoff with 3 retries and a delay factor of 10 seconds
+  // gives you at least 70 seconds to upload a release archive.
   axiosRetry(axios, {
     retries: 3,
-    retryDelay: exponentialDelay,
+    retryDelay: tenSecondExponentialDelay,
     shouldResetTimeout: true,
   });