spec.rb

context 'buyer names changes' do
  let(:name) { 'Lindt' }
  let(:supplier) {  Supplier.create(name: 'Cocoa Beans Inc', email: 'cb@gmail.com', password: 'password')  }
  let(:buyer) { Buyer.cretae(name: name, email: 'lindt@gmail.com', password: 'password') }
  
  subject { 
    FactoryGirl.create(:trade_request, buyer: buyer, supplier: supplier)
  }
  
  # go for a logical context name
  context 'without buyer' do
    it "creates an SP number from the first 4 letters from the client's name, then the first 4 letters from the supplier's name, then a sequential 3 digit number for each trade request with this combination of client and supplier, starting from an optional starting value" do
      expect(subject.sp_number).to eq 'LINDCOCO101'
    end
  end
  
  # go for a logical context name
  context 'with buyer' do
    let!(:name) { 'Cadbury' }
    it "creates an SP number from the first 4 letters from the client's name, then the first 4 letters from the new supplier's name, and increments the sequential 3 digit number from the previous example" do
      expect(subject.sp_number).to eq 'CADBCOCO102'
    end
  end
end