```ruby
require 'test_helper'

class ProgrammeTest < ActiveSupport::TestCase
  def template_programme
    g = Programme.new(:slug=>"childcare", :name=>"Something")
    edition = g.editions.first
    edition.title = 'One'
    g
  end

  test "order parts shouldn't fail if one part's order attribute is nil" do
    g = template_programme
    edition = g.editions.first
    edition.parts.build
    edition.parts.build(:order => 1)
    assert edition.order_parts
  end
end
```

Use the expected class name...
user
```ruby
require 'test_helper'

class ProgrammeEditionTest < ActiveSupport::TestCase
  def template_programme
    g = Programme.new(:slug=>"childcare", :name=>"Something")
    edition = g.editions.first
    edition.title = 'One'
    g
  end

  test "order parts shouldn't fail if one part's order attribute is nil" do
    g = template_programme
    edition = g.editions.first
    edition.parts.build
    edition.parts.build(:order => 1)
    assert edition.order_parts
  end
end
```
assistant