Fixed the upload test

cms/djangoapps/contentstore/features/upload.py

@@ -24,13 +24,10 @@ def go_to_uploads(_step):
 def upload_file(_step, file_name):
     upload_css = 'a.upload-button'
     world.css_click(upload_css)
-
-    file_css = 'input.file-input'
-    upload = world.css_find(file_css)
     #uploading the file itself
     path = os.path.join(TEST_ROOT, 'uploads/', file_name)
-    upload._element.send_keys(os.path.abspath(path))
-
+    world.browser.execute_script("$('input.file-input').css('display', 'block')")
+    world.browser.attach_file('file', os.path.abspath(path))
     close_css = 'a.close-button'
     world.css_click(close_css)