test - unit - move fetch polyfill to helper

test/helper.js

@@ -14,6 +14,9 @@ global.log = log
 // polyfills
 //
 
+// fetch
+global.fetch = require('isomorphic-fetch')
+
 // dom
 require('jsdom-global')()
 

test/unit/app/controllers/currency-controller-test.js

@@ -1,6 +1,3 @@
-// polyfill fetch
-global.fetch = global.fetch || require('isomorphic-fetch')
-
 const assert = require('assert')
 const nock = require('nock')
 const CurrencyController = require('../../../../app/scripts/controllers/currency')

test/unit/config-manager-test.js

@@ -1,6 +1,3 @@
-// polyfill fetch
-global.fetch = global.fetch || require('isomorphic-fetch')
-
 const assert = require('assert')
 const configManagerGen = require('../lib/mock-config-manager')