<NME> field_spec.rb
<BEF> require 'spec_helper'

describe Field do
  it { should have_many :agreement_fields }
end
  it { should allow_mass_assignment_of(:description) }
end

<MSG> Agreement accepts nested agreement_fields

<DFF> @@ -2,4 +2,6 @@ require 'spec_helper'
 
 describe Field do
   it { should have_many :agreement_fields }
+  it { should allow_mass_assignment_of(:label) }
+  it { should allow_mass_assignment_of(:data_type) }
 end

Agreement accepts nested agreement_fields