```ruby
describe CloudNoteMailer do
  describe '.syncdown_note_failed' do
    let(:provider) { 'PROVIDER01' }
    let(:guid) { 'USER01' }
    let(:username) { 'USER01' }
    let(:error) { mock('error', :class => 'ERRORCLASS', :message => 'ERRORMESSAGE', :backtrace => ['ERROR', 'BACKTRACE']) }
    let(:mail) { CloudNoteMailer.syncdown_note_failed(provider, guid, username, error) }
 
    it 'renders the subject' do
      mail.subject.should == I18n.t('notes.sync.failed.email.subject', :provider => provider.titlecase, :guid => guid, :username => username)
    end
 
    it 'renders the receiver email' do
      mail.to.should == [Settings.monitoring.email]
    end
 
    it 'renders the sender email' do
      mail.from.should == [Settings.admin.email]
    end
 
    it 'assigns @name' do
      mail.body.encoded.should match(Settings.monitoring.name)
    end
 
    it 'assigns @user' do
      mail.body.encoded.should match(username)
    end

    it 'assigns @error class' do
      mail.body.encoded.should match('ERRORCLASS')
    end

    it 'assigns @error message' do
      # Is this needed?
      pending "mail.body.encoded.should match('ERRORMESSAGE')"
    end
  end
end
```

Use double instead of mock
user
```ruby
# encoding: utf-8

describe CloudNoteMailer do
  describe '.syncdown_note_failed' do
    let(:provider) { 'PROVIDER01' }
    let(:guid) { 'USER01' }
    let(:username) { 'USER01' }
    let(:error) { double('error', class: 'ERRORCLASS', message: 'ERRORMESSAGE', backtrace: %w(ERROR BACKTRACE)) }
    let(:mail) { CloudNoteMailer.syncdown_note_failed(provider, guid, username, error) }

    it 'renders the subject' do
      mail.subject.should == I18n.t('notes.sync.failed.email.subject', provider: provider.titlecase,
                                                                       guid: guid,
                                                                       username: username)
    end

    it 'renders the receiver email' do
      mail.to.should == [Settings.monitoring.email]
    end

    it 'renders the sender email' do
      mail.from.should == [Settings.admin.email]
    end

    it 'assigns @name' do
      mail.body.encoded.should match(Settings.monitoring.name)
    end

    it 'assigns @user' do
      mail.body.encoded.should match(username)
    end

    it 'assigns @error class' do
      mail.body.encoded.should match('ERRORCLASS')
    end

    it 'assigns @error message' do
      # Is this needed?
      pending "mail.body.encoded.should match('ERRORMESSAGE')"
    end
  end
end
```
assistant