swap_for_bundle_products_spec.rb

  context "when there are shipments that have bundleable products" do
    let(:shipments_in) { [shipment1, shipment2] }
    let(:shipment1) { build(:shipment, products: [product_a]) }
    let(:shipment2) { build(:shipment, products: [product_b]) }

    it "returns the bundling product instead of the bundleable ones" do
      expect(shipments_out.first.products).to match_array(product_c)
    end

    it "does not return the unused shipment" do
      expect(shipments_out.count).to eq 1
    end