test: fix api.test expectations and move test-helpers out of __tests__

Author: abueide

packages/core/src/__tests__/api.test.ts

@@ -72,6 +72,7 @@ describe('#sendEvents', () => {
       headers: {
         'Content-Type': 'application/json; charset=utf-8',
       },
+      keepalive: true,
     });
   }
 

packages/core/src/backoff/__tests__/BackoffManager.test.ts

@@ -2,11 +2,11 @@ import { BackoffManager } from '../BackoffManager';
 import type { Persistor } from '@segment/sovran-react-native';
 import type { BackoffConfig } from '../../types';
 import { getMockLogger } from '../../test-helpers';
-import { createTestPersistor } from './test-helpers';
+import { createTestPersistor } from '../test-helpers';
 
 jest.mock('@segment/sovran-react-native', () => {
   // eslint-disable-next-line @typescript-eslint/no-var-requires
-  const helpers = require('./test-helpers');
+  const helpers = require('../test-helpers');
   return {
     ...jest.requireActual('@segment/sovran-react-native'),
     createStore: jest.fn((initialState: unknown) =>

packages/core/src/backoff/__tests__/UploadStateMachine.test.ts

@@ -2,11 +2,11 @@ import { UploadStateMachine } from '../UploadStateMachine';
 import type { Persistor } from '@segment/sovran-react-native';
 import type { RateLimitConfig } from '../../types';
 import { getMockLogger } from '../../test-helpers';
-import { createTestPersistor } from './test-helpers';
+import { createTestPersistor } from '../test-helpers';
 
 jest.mock('@segment/sovran-react-native', () => {
   // eslint-disable-next-line @typescript-eslint/no-var-requires
-  const helpers = require('./test-helpers');
+  const helpers = require('../test-helpers');
   return {
     ...jest.requireActual('@segment/sovran-react-native'),
     createStore: jest.fn((initialState: unknown) =>