Can not get proxyquire to work with a require that happens in an init function

[intervalia]

I have some code like this:

/lib/mine.js

const path = require('path');

function init(cfg) {
  var inner = require(cfg.file);
  inner.doSomething();
}

module.exports = {init};

/app.js

const mine = require(('./lib/mine');
// Do some stuff here

const cfg = {
  file: '../otherPath/otherFile'
};

mine.init(cfg);

The code is much more complicated then this, but this is close enough to show the problem.

I am writing tests for app.js above and want to use proxyquire for the file ../otherPath/otherFile

My test file is like this:

app.mocha.js

const proxyquire = require('proxyquire').noCallThru();

const ofStub = {
  doSomething: function() {
    // Do something
  }
}

const app = proxyquire('./app', {
  '../otherPath/otherFile': ofStub
});

The rest of this file does not matter since the error happens when I try to use proxyquire on app

I get something like the following error:

Error: Cannot find module '../otherPath/otherFile

The thing is that it should not have tried to load that module yet since I have not called init

Is there a way to force proxyquire to not care if the real module was loaded using require when proxyquire is initially called and just allow the module to be overridden if and when it is loaded?

[bendrucker]

Hey, would you mind creating a simple repro project with this case? I think I understand what you're trying to do here but it'd be a big help to be able to see the error and debug it directly.

[intervalia]

The failing code is in a private repo but I will create a public repo that demos the bug.

I will respond to this thread as soon as it is ready but I may not be able to get to it until Monday.

Thanks!!

[bendrucker]

Cool, thank you! I'll leave this open while you work on that.

[bendrucker]

An ideal repro project is setup such that we can npm install && npm test and get an exception.

[intervalia]

OK. Maybe there isn't an error in your code. It looks like my code must be at fault.

Here is the repo I created so you can see what I was doing.
https://github.com/intervalia/proxyquire-215
It does pass tests. So I will dig further into my other code and let you know what I find.

But I really think it is my issue now and not yours.

[bendrucker]

😄 Thanks, that often happens with a repro, hopefully it's a helpful exercise!

[intervalia]

I figured out what happened that made me think this was a bug.

In my tests I was using const proxyquire = require('proxyquire').noCallThru();

I had assumed that since I was telling proxyquire to NOT use the original required code that it would not bother trying to load the original file.

In my test code I was telling the system to require a non-existent file. And Proxyquire complained that the file didn't exist.

To me this felt off since I didn't need it to exist in my tests. I was overriding it through a stub after all.

So it may not be a real bug, but it felt like one since I said .noCallThru().

So maybe allow proxyquire to not bother checking to see if a file really exists when using .noCallThru() then my tests would not have failed.

Without change I now have to force the existence of a file, in my test environment, that is never used. If .noCallThru() didn't care about the existence of the required file then my code would have worked fine.

So maybe it is WAD (Working as Designed), but it seems like a nice option to ignore the existence of any file that is stubbed out when using .noCallThru().

If you guys want to mark this as WAD, that's fine, but maybe add some docs letting people know that every requireed file must exist even if you stub it out with .noCallThru() enabled.

OR: Maybe add an option into .noCallThru(false) that prevents the file exists code.

[bendrucker]

This is the output I get:

____ load.js loaded
Stubbed success.js called


  proxyquire issue #215 tests
TESTING Lazy loading files from ../lazyload/one
____ load.js run
loading ../lazyload/one
running ../lazyload/one
Stubbed one.js called

Proxyquire only tries to load the original to provide call-thru functionality. Setting noCallThru() should eliminate any need to have the stubbed modules actually present.

Please do modify your example if I'm misunderstanding since as long as the tests are passing I expect it's working.

[intervalia]

Sorry, I forgot to change my repo. It is now changed and shows the failure.

Again, this is a test only environment for me. I have a situation where I want to only stub out a file that does not exist. The code shows that. It used to require '../lazyload/one', which exists. Not it attempts to require '../lazyload/two' which does not exist but it 100% stubbed out in my test file (app.mocha.js).

[bendrucker]

Hmm, interesting. Looking into it.

[bendrucker]

From some quick debugging I see that these errors are rethrown unless noPreserveCache() is on:

proxyquire/lib/proxyquire.js

Lines 157 to 159 in 68df3d1

	if (!this._preserveCache) {
	return path.resolve(path.dirname(baseModule), pathToResolve)
	}

For now you can probably go ahead and turn that option on.

It seems to me like that functionality should be tied to noCallThru instead of or at least in addition to noPreserveCache. I'll look into changing that.

[intervalia]

I'll check it within the hour.

[intervalia]

Yes. My bug is now gone. Thanks for the quick fix!!