Ruby on Rails

Hello all,

I am trying to understand when I try to run a test in cucumber what I am missing that it is failing. I am using FactoryGirl to create my records and using cucumber to test my logic however I know that I am doing something wrong in my testing I just can't seem to figure out what. Here is what I have:

Feature:

Feature: All features related to staff info
  Scenario: notification for empty shirt size
    Given there is at least 1 staff info record
    When the shirt size field is empty
    And the shirt size check is run
    Then the system should send an email notification

Steps:

Given(/^there is at least (\d+) staff info record$/) do |arg1|
  assert_difference('StaffInfo.count', 1) do
    @staff_info = FactoryGirl.create :staff_info
  end
end

When(/^the shirt size field is empty$/) do
  assert @staff_info.update_attribute(:shirt_size, nil)
end

When(/^the shirt size check is run$/) do
  StaffInfo.check_empty_shirt_fields
end

Then(/^the system should send an email notification$/) do
  pending # express the regexp above with the code you wish you had
end

Model:

class StaffInfo < ActiveRecord::Base
  belongs_to :person
  scope :empty_shirt_fields, -> { where('shirt_size in (?)', [nil, '']) }
 
  def self.check_empty_shirt_fields
    staff_with_missing_shirt_sizes = StaffInfo.empty_shirt_fields
    debugger
    send_empty_shirt_size_notification staff_with_missing_shirt_sizes if staff_with_missing_shirt_sizes.size >  0
  end
 
  def send_empty_shirt_size_notification(staff_records)
    Mailer.missing_shirt_size(staff_records).deliver
  end
end

What is happening is, when I hit the 3rd test I did a check to see if the record was present (StaffInfo.count) and it was. But after running   StaffInfo.check_empty_shirt_fields, I did a check for the record and it was gone. I am not understanding how my record could have disappeared when I all my method was doing was checking for any records with a missing field.

Anyone have any ideas?