fix: Add override OS and linux default

src/helpers.test.ts

@@ -0,0 +1,61 @@
+import {
+  getBaseUrl,
+  getPlatform,
+  isValidPlatform,
+  isWindows,
+  PLATFORMS,
+} from './helpers';
+
+let OLDOS = process.env.RUNNER_OS;
+
+beforeEach(() => {
+  jest.resetModules();
+  OLDOS = process.env.RUNNER_OS;
+});
+
+afterAll(() => {
+  process.env.RUNNER_OS = OLDOS;
+});
+
+test('getPlatform', () => {
+  expect(getPlatform('linux')).toBe('linux');
+  expect(getPlatform('windows')).toBe('windows');
+
+  const defaultPlatform =
+      process.env.RUNNER_OS ? process.env.RUNNER_OS.toLowerCase() : 'linux';
+  expect(getPlatform('fakeos')).toBe(defaultPlatform);
+  expect(getPlatform()).toBe(defaultPlatform);
+
+  process.env.RUNNER_OS = 'macos';
+  expect(getPlatform('fakeos')).toBe('macos');
+  expect(getPlatform()).toBe('macos');
+
+  process.env.RUNNER_OS = 'alsofakeos';
+  expect(getPlatform()).toBe('linux');
+  expect(getPlatform('fakeos')).toBe('linux');
+});
+
+test('getBaseUrl', () => {
+  expect(PLATFORMS.map((platform) => {
+    return getBaseUrl(platform);
+  })).toEqual([
+    'https://uploader.codecov.io/latest/alpine/codecov',
+    'https://uploader.codecov.io/latest/linux/codecov',
+    'https://uploader.codecov.io/latest/macos/codecov',
+    'https://uploader.codecov.io/latest/windows/codecov.exe',
+  ]);
+});
+
+test('isWindows', () => {
+  expect(PLATFORMS.map((platform) => {
+    return isWindows(platform);
+  })).toEqual([false, false, false, true]);
+});
+
+test('isValidPlatform', () => {
+  expect(PLATFORMS.map((platform) => {
+    return isValidPlatform(platform);
+  })).toEqual([true, true, true, true]);
+
+  expect(isValidPlatform('fakeos')).toBeFalsy();
+});