Given I already have a server up and running on localhost (see further down for an example), at a node command line while online, I get the following:
> var x = request('http://localhost:8080/test.html',
... function(err) { if (err) console.log(err) })
undefined
>
I expect to get the above result all the time.
If I've switched to flight mode I get the following:
> var x = request('http://localhost:8080/test.html',
... function(err) { if (err) console.log(err) })
undefined
> { Error: getaddrinfo ENOENT localhost:8080
at Object.exports._errnoException (util.js:1022:11)
at errnoException (dns.js:33:15)
at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:76:26)
code: 'ENOENT',
errno: 'ENOENT',
syscall: 'getaddrinfo',
hostname: 'localhost',
host: 'localhost',
port: '8080' }
Trying this again with 127.0.0.1 instead of localhost works whether or not I'm in flight mode.
Question
Why does localhost not work? I can see it's something to do with Windows's DNS resolver.
Setup for the client code above
You need to install the require first:
C:\> npm install require
Broader context
I've boiled this down to the simplest I can. See Why does web-component-tester time out in flight mode? for the broader context.
Example server
The question isn't about the following server specifically, it's just a quick example. I think probably any local server would do, not just a NodeJS one. The problem is in the client code as detailed above.
Setup for the example server:
C:\> npm install connect serve-static
server.js:
var connect = require('connect')
var serveStatic = require('serve-static')
connect().use(serveStatic(__dirname)).listen(8080)
test.html:
<html>Really not important, but necessary for completeness</html>
Start the server:
C:\> node server.js
The solution is to install the Microsoft Loopback Adapter, as detailed below: