cypress_mocks.js

// option 1 to override fetch, using cypress built-in facilities (e.g. sinon)

cy
    // sinon syntax ⬇️
    .stub(win, 'fetch')
    .withArgs('/graphql')

// The pseudocode-ish that this generates, kinda like this:
const realFetch = window.fetch
window.fetch = (arg1) => {
  if (arg1 === '/grapqhl') {
    doFakeStuff()
  }
  else {
    return realFetch(arg1)
  }
}



// option 2 to override fetch (again pseudocode)
// seems like this is necessary since sinon2.0 because of the "thennable" issue

myFakeFetch = {
  // whatever...
}
cy.window(win => {
  win.fetch = myFakeFetch
})