nconf values are undefined when a module is rewire

[chavan-gopal]

I have the following situation and wanted to understand what would be the best way to handle it.
So in my project I am using nconf for managing configuration settings in applications. and for running test-cases I set nconf with test.json file which have all configuration variables(like PORT, DB_HOST, S3_BUCKET_URL etc)

const nconf = require('nconf').argv().env()
nconf.file({file: path_to_test.json})

and following is the module which I wan to rewire in my test-case
module.js

const nconf = require('nconf')
...
// I have added below code for simplicity
if(!nconf.get('port')){
throw error('error')
}
...

in my test-case I am rewiring a module(this module also makes use of nconf)
test-case.js

const nconf = require('nconf') // here I could access all env vars PORT, DB_HOST etc
const rewire = require('rewire')
const myModule = rewire('path_to_module') // here I would get error and test-execution stop's here
// because nconf.get('port') is undefined

How can I resolve this issue, so nconf retains its value when rewiring the module