Promise doesn't work with jest in REACTJS - reactjs

Question

I keep having a TypeError: Network request failed when I try to test a Snapshot of a component
here is the component
import {GetAllUsersPost} from './postdata';
class ManageUsers extends React.Component{
render(){
return(
{...}
);
}
componentDidMount(){
GetAllUsersPost(UserProfile.getId()).then((result) => {
this.setState({
parsed:result,
loading:false
})
});
}
}
Here is postdata
export function GetAllUsersPost(id) {
const json = JSON.stringify({id: id})
return new Promise((resolve, reject) => {
fetch(BaseURL + 'allusers', BdRequest(json)).then((response) => response.json()).then((res) => {
resolve(res);
}).catch((error) => {
reject(error);
});
});
}
And here is the test file (\src__tests__\ManageUsers.test.jsx)
import React from 'react';
import ManageUsers from '../component/ManageUsers';
import Adapter from 'enzyme-adapter-react-16';
import Enzyme, {shallow,mount} from 'enzyme';
Enzyme.configure({adapter:new Adapter()});
describe("ManageUsers", ()=>{
const wrapper = shallow(<ManageUsers/>);
const instance = wrapper.instance();
let response;
test("loading()",()=>{
wrapper.setState({loading:false})
response = JSON.stringify("")
expect(JSON.stringify(instance.loading())).toBe(response);
})
});
I know that my error is because of the promise (when Enzyme tries to shallow the component) but I can't make it to work...
thanks

Answer 1

Your test has to be set up as an async test. e.g.
it('should do something', async () => {
const result = await myAsyncMethod();
});
Edited for clarity - note that this is clearly untested, but what you need to look for is something from the render method and state, since that's all you do with the results.
import React from 'react';
import ManageUsers from '../component/ManageUsers';
import Adapter from 'enzyme-adapter-react-16';
import Enzyme, {shallow,mount} from 'enzyme';
Enzyme.configure({adapter:new Adapter()});
describe("ManageUsers", () => {
const wrapper = shallow(<ManageUsers/>);
test("loading()", async () => {
// wrapper.setState({loading:false}) // This should be a default
expect(wrapper.find('something from the render'));
expect(wrapper.state.parsedResults).toEqual('some result')
});
});