title: How to write rspec test cases to cover failure of object save
body: <p>I have following code</p>
  
  <pre><code>@support_report.notes = params[:support_report][:notes]
    if @support_report.save
      redirect_to admins_support_reports_path, notice: t('admins.support_reports.add_notes.successfully')
    else
      redirect_to admins_support_reports_path, alert: t('admins.support_reports.add_notes.no_change')
    end
  </code></pre>
  
  <p>In this am just updating 'notes' attribute which is not having any validation.
  I have to cover 'else' part inside rspec coverage.
  How can I do it, please suggest some way</p>