diff --git a/spec/api-browser-window-spec.js b/spec/api-browser-window-spec.js
index 5d23170edee1..6a839d91aa03 100644
--- a/spec/api-browser-window-spec.js
+++ b/spec/api-browser-window-spec.js
@@ -698,7 +698,7 @@ describe('browser-window module', function () {
         })
         let htmlPath = path.join(fixtures, 'api', 'sandbox.html?window-open-external')
         const pageUrl = 'file://' + htmlPath
-        let openedWindow
+        let popupWindow
         w.loadURL(pageUrl)
         w.webContents.once('new-window', (e, url, frameName, disposition, options) => {
           assert.equal(url, 'http://www.google.com/#q=electron')
@@ -712,15 +712,18 @@ describe('browser-window module', function () {
             ipcMain.once('answer', function (event, exceptionMessage) {
               assert(/Blocked a frame with origin/.test(exceptionMessage))
 
-              // FIXME this opened window should be closed in sandbox.html
-              closeWindow(openedWindow).then(done)
+              // FIXME this popup window should be closed in sandbox.html
+              closeWindow(popupWindow).then(() => {
+                popupWindow = null
+                done()
+              })
             })
             w.webContents.send('child-loaded')
           })
         })
 
         app.once('browser-window-created', function (event, window) {
-          openedWindow = window
+          popupWindow = window
         })
       })