diff --git a/__tests__/distributors/jetbrains-installer.test.ts b/__tests__/distributors/jetbrains-installer.test.ts
index 44d8ef89..07d6219e 100644
--- a/__tests__/distributors/jetbrains-installer.test.ts
+++ b/__tests__/distributors/jetbrains-installer.test.ts
@@ -3,10 +3,10 @@ import {HttpClient} from '@actions/http-client';
 import {JetBrainsDistribution} from '../../src/distributions/jetbrains/installer';
 
 import manifestData from '../data/jetbrains.json';
-import os from 'os';
 
 describe('getAvailableVersions', () => {
   let spyHttpClient: jest.SpyInstance;
+  let spyHttpClientHead: jest.SpyInstance;
 
   beforeEach(() => {
     spyHttpClient = jest.spyOn(HttpClient.prototype, 'getJson');
@@ -15,6 +15,10 @@ describe('getAvailableVersions', () => {
       headers: {},
       result: []
     });
+    spyHttpClientHead = jest.spyOn(HttpClient.prototype, 'head');
+    spyHttpClientHead.mockReturnValue({
+      message: {statusCode: 200}
+    });
   });
 
   afterEach(() => {
@@ -40,9 +44,8 @@ describe('getAvailableVersions', () => {
     const availableVersions = await distribution['getAvailableVersions']();
     expect(availableVersions).not.toBeNull();
 
-    const length =
-      os.platform() === 'win32' ? manifestData.length : manifestData.length + 2;
-    expect(availableVersions.length).toBe(length);
+    // manifestData items + 2 hidden versions (always included when head is mocked to return 200)
+    expect(availableVersions.length).toBe(manifestData.length + 2);
   }, 10_000);
 });