Update RSpec for Product Item model

spec/factories/product_item.rb

+FactoryGirl.define do
+  factory :product_item do
+    quantity 1
+    product
+    order
+  end
+end

spec/models/order_spec.rb

@@ -21,10 +21,8 @@ RSpec.describe Order, type: :model do
       user = create(:user)
       user = create(:user)
       order = create(:order, user: user)
       order = create(:order, user: user)
       product = create(:product, quantity: 3, price: 10)
       product = create(:product, quantity: 3, price: 10)
-      ProductItem.create(quantity: 2,
-                         product_id: product.id,
-                         order: order)
-      expect(order.total_price).to eq 20
+      create(:product_item, product: product, order: order)
+      expect(order.total_price).to eq 10
     end
     end
   end
   end
 end
 end

spec/models/product_item_spec.rb

@@ -15,4 +15,18 @@ RSpec.describe ProductItem, type: :model do
     it { is_expected.to belong_to(:order) }
     it { is_expected.to belong_to(:order) }
     it { is_expected.to belong_to(:product) }
     it { is_expected.to belong_to(:product) }
   end
   end
+
+  context 'custom methods' do
+    let!(:product) { create(:product, price: 10, quantity: 3) }
+    let!(:product_item) { create(:product_item, product: product) }
+
+    it 'has valid total_price' do
+      expect(product_item.total_price).to eq 10
+    end
+
+    it 'has valid update_product_quantity' do
+      product_item.update_product_quantity
+      expect(product.quantity).to eq 2
+    end
+  end
 end
 end

spec/models/product_spec.rb

@@ -31,6 +31,10 @@ RSpec.describe Product, type: :model do
       expect(product.in_stock?(2)).to be_truthy
       expect(product.in_stock?(2)).to be_truthy
     end
     end
 
 
+    it 'has invalid in_stock?' do
+      expect(product.in_stock?(4)).not_to be_truthy
+    end
+
     it 'has valid belongs_to_user?' do
     it 'has valid belongs_to_user?' do
       expect(product.belongs_to_user?(user)).not_to be_truthy
       expect(product.belongs_to_user?(user)).not_to be_truthy
     end
     end