How to write test cases for react native api calls using Jest?

I am using apiSauce library for api calls and I am facing issue while writing jest for api class methods.

ChemicalListApi.ts

import { ApiResponse } from 'apisauce';import { RestService } from '../RestService';import { ApiConfig } from '../serviceConfig';import { GetChemicalsRequest } from '../../Types/Chemical/chemicalListTypes';const api = new RestService();export class ChemicalListApi {  chemicalsListApi = (queryParams: GetChemicalsRequest): Promise<ApiResponse<any>> => {    return api.apiCall(ApiConfig.CHEMICAL_LIST_DATA, { queryParams });  };}

__test __/RegistrationApi.test.ts

import { ChemicalListApi } from '../chemicalServices/ChemicalListApi';describe('EmailService', () => {  let instance: ChemicalListApi;  beforeEach(() => {    instance = new ChemicalListApi();  });  it('should get all users as an array', async () => {    expect(instance).toBeInstanceOf(ChemicalListApi);    const allUsers = await instance.chemicalsListApi({});    expect(allUsers).toBeDefined();  });});

Result:

Test Suites: 1 passed, 1 totalTests:       1 passed, 1 totalSnapshots:   0 totalTime:        2.761s, estimated 3sRan all test suites matching /RegistrationApi.test.ts/i.Jest did not exit one second after the test run has completed.This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with `--detectOpenHandles` to troubleshoot this issue.✨  Done in 34.62s.

Problem :

chemicalsListApi method is async method , by writing test cases like above is triggering api call. so I am getting warning like : 'This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with --detectOpenHandles to troubleshoot this issue.'