Iteration B1.

app/models/product.rb

@@ -1,2 +1,9 @@
 class Product < ApplicationRecord
+  validates :title, :description, :image_url, :price, presence: true
+  validates :price, numericality: {greater_than_or_equal_to: 0.01}
+  validates :title, uniqueness: true
+  validates :image_url, allow_blank: true, format: {
+    with: %r{\.(gif|jpg|png)\Z}i,
+    message: 'must be URL for GIF, JPG or PNG image.'
+  }
 end

test/controllers/products_controller_test.rb

@@ -3,6 +3,12 @@ require 'test_helper'
 class ProductsControllerTest < ActionDispatch::IntegrationTest
   setup do
     @product = products(:one)
+    @update = {
+      title: 'Lorem Ipsum',
+      description: 'Wibbles are fun!',
+      image_url: 'lorem.jpg',
+      price: 19.95
+    }
   end
 
   test "should get index" do
@@ -17,7 +23,7 @@ class ProductsControllerTest < ActionDispatch::IntegrationTest
 
   test "should create product" do
     assert_difference('Product.count') do
-      post products_url, params: { product: { description: @product.description, image_url: @product.image_url, price: @product.price, title: @product.title } }
+      post products_url, params: { product: @update }
     end
 
     assert_redirected_to product_url(Product.last)
@@ -34,7 +40,7 @@ class ProductsControllerTest < ActionDispatch::IntegrationTest
   end
 
   test "should update product" do
-    patch product_url(@product), params: { product: { description: @product.description, image_url: @product.image_url, price: @product.price, title: @product.title } }
+    patch product_url(@product), params: { product: @update }
     assert_redirected_to product_url(@product)
   end