Correctly handle devMode

src/browser/main.coffee

@@ -8,13 +8,13 @@ yargs = require 'yargs'
 console.log = require 'nslog'
 
 start = ->
+  args = parseCommandLine()
+
   setupUncaughtExceptionHandler()
-  setupAtomHome()
+  setupAtomHome(args)
   setupCompileCache()
   return if handleStartupEventWithSquirrel()
 
-  args = parseCommandLine()
-
   addPathToOpen = (event, pathToOpen) ->
     event.preventDefault()
     args.pathsToOpen.push(pathToOpen)
@@ -56,21 +56,23 @@ handleStartupEventWithSquirrel = ->
 setupCrashReporter = ->
   crashReporter.start(productName: 'Atom', companyName: 'GitHub')
 
-isPortableInstall = ->
+isPortableInstall = (args) ->
   return false unless process.platform is 'win32'
   return false unless (process and process.type)
+  return false if args.devMode or args.testMode
 
   ourPath = process.execPath.toLowerCase()
   return (ourPath.indexOf(process.env.LOCALAPPDATA.toLowerCase()) is 0)
 
-setupAtomHome = ->
+setupAtomHome = (args) ->
   return if process.env.ATOM_HOME
+
   atomHome = path.join(app.getHomeDir(), '.atom')
   try
     atomHome = fs.realpathSync(atomHome)
     fs.statSync(atomHome)
   catch
-    atomHome = path.join(path.dirname(process.execPath), '.atom') if isPortableInstall()
+    atomHome = path.join(path.dirname(process.execPath), '.atom') if isPortableInstall(args)
 
   process.env.ATOM_HOME = atomHome