openfoodnetwork/spec/models/concerns/product_stock_spec.rb

require "spec_helper"

describe ProductStock do
  let(:product) { create(:simple_product) }

  context "when product has no variants" do
    before do
      product.variants.first.destroy
      product.variants.reload
    end

    describe "product.on_demand" do
      it "is master.on_demand" do
        expect(product.on_demand).to eq(product.master.on_demand)
      end
    end

    describe "product.on_hand" do
      it "is master.on_hand" do
        expect(product.on_hand).to eq(product.master.on_hand)
      end
    end
  end

  context "when product has one variant" do
    describe "product.on_demand" do
      it "is the products first variant on_demand" do
        expect(product.on_demand).to eq(product.variants.first.on_demand)
      end
    end

    describe "product.on_hand" do
      it "is the products first variant on_hand" do
        expect(product.on_hand).to eq(product.variants.first.on_hand)
      end
    end
  end

  context 'when product has more than one variant' do
    before do
      product.variants << create(:variant, product: product)
    end

    describe "product.on_demand" do
      it "raises error" do
        expect { product.on_demand }
          .to raise_error(StandardError, /Cannot determine product on_demand value/)
      end
    end

    describe "product.on_hand" do
      it "is the sum of the products variants on_hand values" do
        expect(product.on_hand).to eq(product.variants.first.on_hand + product.variants.second.on_hand)
      end
    end
  end
end