Putting in a small snippet below :
import xyz from '../xyz'
function calculate() {
return xyz(arg1, arg2).catch((err) => {
func1()
func2()
})
}
export default calculate
I'm just trying to assert that xyz is called in jest. How can I do it ?
I tried the following but doesn't work :
import * as myModule from '../xyz'
import calculate from '../../calculate'
const mock = jest.spyOn(myModule, 'xyz')
mock.mockReturnValue('mocked value')
const op = calculate()
expect(op).toBe('mocked value')
This gives me the following error:
Cannot spy the xyz property because it is not a function; undefined given instead
You can mock the module like this:
import calculate from '../../calculate'
jest.mock('../xyz', ()=> () => Promise.resolve('mocked value'))
it('does something', async()=>{
const op = await calculate()
expect(op).toBe('mocked value')
})
if you need different return values from your mock you need to mock the module so it returns a spy. Then you have to import the module and you can set the return value during your tests:
import calculate from '../../calculate'
import myModule from '../xyz'
jest.mock('../xyz', ()=> jest.fn())
it('does something', async() => {
myModule.mockImplementation(() => () => Promise.resolve('mocked value'))
const op = calculate()
expect(op).toBe('mocked value')
})
it('does something else', async() => {
myModule.mockImplementation(() => () => Promise.resolve('another value'))
const op = await calculate()
expect(op).toBe('another value')
})
it('does fail', async() => {
myModule.mockImplementation(() => () => Promise.reject('some Error')
try{
const op = await calculate()
}catch (e){
expect(e).toBe('some Error')
}
})