def METHOD_NAME(self):
    interface, view = yield from self.await_std_interface()
    when(GitCommand).stage_file(...)
    view.run_command('gs_status_stage_file')
    verify(GitCommand).stage_file('modified_file', 'new_file', 'conflicting_file', ...)
    verify(interface).refresh_repo_status_and_render()
    verify(view.window()).status_message("Staged files successfully.")