closeWindow in an afterEach block

spec/api-web-frame-spec.js

@@ -6,6 +6,11 @@ const {BrowserWindow, protocol, ipcMain} = remote
 
 describe('webFrame module', function () {
   var fixtures = path.resolve(__dirname, 'fixtures')
+  var w = null
+
+  afterEach(function () {
+    return closeWindow(w).then(function () { w = null })
+  })
 
   describe('webFrame.registerURLSchemeAsPrivileged', function () {
     it('supports fetch api by default', function (done) {
@@ -96,17 +101,14 @@ describe('webFrame module', function () {
       runNumber++
 
       const url = standardScheme + '://fake-host'
-      var w = new BrowserWindow({show: false})
+      w = new BrowserWindow({show: false})
       after(function (done) {
         protocol.unregisterProtocol(corsScheme, function () {
           protocol.unregisterProtocol(standardScheme, function () {
-            closeWindow(w).then(function () {
-              w = null
             done()
           })
         })
       })
-      })
 
       const handler = function (request, callback) {
         callback({data: content, mimeType: 'text/html'})