Add log global to test suite

test/helper.js

@@ -1,5 +1,11 @@
+var log = require('loglevel')
+log.setDefaultLevel(5)
+
 require('jsdom-global')()
 window.localStorage = {}
 
 if (!('crypto' in window)) { window.crypto = {} }
 window.crypto.getRandomValues = require('polyfill-crypto.getrandomvalues')
+
+window.log = log
+global.log = log