How to mock auto inputs to test prompt function

[aliuq]

I write a function to wrap prompt function, and I trying to write a test case, I don't know how to mock user input, Have any ideas to mock it?

import { assertEquals } from 'https://deno.land/std@0.147.0/testing/asserts.ts'

Deno.test('Function - wrapPrompt', async () => {
  const res = await wrapPrompt('prompt') // Terminal stoped here
  await Deno.stdout.write(new TextEncoder().encode('y\n'))
  assertEquals(res, 'y')
})

[zachauten]

You'll want to use the stub function from the testing lib. prompt exists on the global object (window), so create the stub like this:

import { stub } from "https://deno.land/std@0.148.0/testing/mock.ts";

// Calls to prompt will always return the same string.
const prompt_stub = stub(window, "prompt", (s) => "mocked input value");

// Restore prompt to it's un-stubbed state
prompt_stub.restore();

[aliuq]

There may also be some internal errors

[zachauten]

Hard to say what your code is doing without seeing wrapPrompt

[aliuq]

wrapPrompt is here

https://github.com/aliuq/deno_module/blob/master/lib/utils.ts#L52

[zachauten]

I would try stepping through it in the debugger to see what args prompt is called with.