```ruby
require 'rails_helper'

RSpec.describe Event, type: :model do

  it { is_expected.to validate_presence_of(:shift_length)}
  it { is_expected.to validate_presence_of(:address)}

  it { is_expected.to have_many(:shifts).dependent(:destroy) }

end
```

Add spec for accepting nested shift attributes
user
```ruby
require 'rails_helper'

RSpec.describe Event, type: :model do

  it { is_expected.to validate_presence_of(:shift_length)}
  it { is_expected.to validate_presence_of(:address)}

  it { is_expected.to have_many(:shifts).dependent(:destroy) }

  it { is_expected.to accept_nested_attributes_for(:shifts) }
end
```
assistant