An example test that tests an axios call is made in a Vue component's mounted() function

mounted-test.spec.js

import Vue from 'vue'
import { mount } from '@vue/test-utils'
import expect from 'expect'
import axios from 'axios'
import moxios from 'moxios'
import sinon from "sinon"

describe ('Test axios in mounted()', () => {
    let wrapper

    let Mounted = Vue.component('Mounted',
        {
            template: `<div></div>`,
            data() {
                return {
                    data: {}
                }
            },
            mounted() {
                this.fetch()
            },
            methods: {
                async fetch() {
                    let data = await axios.post('/test', {param: 'example'})
                    this.data = data
                }
            }
        }
    )

    beforeEach(() => {
        // Ajax stub
        moxios.install()
        wrapper = mount(Mounted)
    })

    afterEach(() => {
        // Ajax stub
        moxios.uninstall()
    })

    it ('should send off a request when mounted', (done) => {
        // Given we set up axios to return something
        moxios.stubRequest('/test', {
            status: 200,
            response: []
        })

        // When the wrapper was mounted
        wrapper = mount(Mounted)

        moxios.wait(() => {
            // It should have called axios
            done()
        })
    })
})