Recursive noPreserveCache: deps should also be reloaded

[axelpale]

I am using proxyquire to unit test a module. I test how the module behaves when certain environment variables are absent or invalid. A dependency of the module also relies on some relevant environment variables. For each test case, I change the env vars and call proxyquire on the module. For the module to reload the new env vars, I use var proxyquire = require('proxyquire').noPreserveCache().

The problem: Even though the env vars of the module become reloaded, the env vars of the dependency do not seem to change after the first `proxyquire(...)' call. It looks like that the dependency becomes cached. I expected the deps to be reloaded also.

Consider a minimal example. Here is a locally available module 'getPort':

const port = process.env.PORT
module.exports = () => { return port }

Then, here is a module 'getHost' that depends on 'getPort':

const getPort = require('getPort')
const host = process.env.HOST
module.exports = () => { return host + getPort() }

Next, here is a unit test suite:

var test = require('tape')
var proxyquire = require('proxyquire').noPreserveCache()
var unit

test('env vars', (t) => {
  process.env.PORT = 8888
  process.env.HOST = 'localhost'
  unit = proxyquire('getHost', {})
  t.equal(unit(), 'localhost:8888')  // success

  process.env.PORT = 8000
  process.env.HOST = 'example.com'
  unit = proxyquire('getHost', {})
  t.equal(unit(), 'example.com:8000')
  // fails, "example.com:8888" does not equal "example:8000"

  t.end()
})

There seems to be an inconvenient way to hack this through. I had to use the following approach after the first proxyquire call to force also the deps to reload:

unit = proxyquire('getHost', {
  'getPort': proxyquire('getPort', {})
})

I hope this issue brings you some insight how people are using the module, in addition to the problem.