Iteration E3.

app/assets/stylesheets/carts.scss

@@ -1,3 +1,13 @@
 // Place all the styles related to the Carts controller here.
 // They will automatically be included in application.css.
 // You can use Sass (SCSS) here: http://sass-lang.com/
+.carts {
+  .item_price, .total_line {
+    text-align: right;
+  }
+
+  .total_line .total_cll {
+    font-weight: bold;
+    border-top: 1px solid #595
+  }
+}

app/controllers/carts_controller.rb

@@ -56,9 +56,10 @@ class CartsController < ApplicationController
   # DELETE /carts/1
   # DELETE /carts/1.json
   def destroy
-    @cart.destroy
+    @cart.destroy if @cart.id == session[:cart_id]
+    session[:cart_id] = nil
     respond_to do |format|
-      format.html { redirect_to carts_url, notice: 'Cart was successfully destroyed.' }
+      format.html { redirect_to store_index_url, notice: 'Your cart is currently empty.' }
       format.json { head :no_content }
     end
   end

app/controllers/line_items_controller.rb

@@ -33,7 +33,7 @@ class LineItemsController < ApplicationController
 
     respond_to do |format|
       if @line_item.save
-        format.html { redirect_to @line_item.cart, notice: 'Line item was successfully created.' }
+        format.html { redirect_to @line_item.cart }
         format.json { render :show, status: :created, location: @line_item }
       else
         format.html { render :new }

app/models/cart.rb

@@ -10,4 +10,9 @@ class Cart < ApplicationRecord
     end
     current_item
   end
+
+  def total_price
+    # QUESTION: How and why? :-D
+    line_items.to_a.sum { |item| item.total_price }
+  end
 end

app/models/line_item.rb

@@ -1,4 +1,8 @@
 class LineItem < ApplicationRecord
   belongs_to :product
   belongs_to :cart
+
+  def total_price
+    product.price * quantity
+  end
 end

app/views/carts/show.html.erb

@@ -1,9 +1,21 @@
 <p id="notice"><%= notice %></p>
 
-<h2>Your Pragmatic Cart</h2>
+<h2>Your Cart</h2>
 
-<ul>
+<table>
   <% @cart.line_items.each do |item| %>
-    <li><%= item.quantity %> &times; <%= item.product.title %></li>
+    <tr>
+      <td><%= item.quantity %> &times;</td>
+      <td><%= item.product.title %></td>
+      <td class="item_price"><%= number_to_currency(item.total_price) %></td>
+    </tr>
   <% end %>
-</ul>
+
+  <tr class="total_line">
+    <td colspan="2">Total</td>
+    <td class="total_cell"><%= number_to_currency(@cart.total_price) %></td>
+  </tr>
+
+</table>
+
+<%= button_to 'Empty Cart', @cart, method: :delete, data: { confirm: 'Are you sure?'} %>

test/controllers/carts_controller_test.rb

@@ -39,10 +39,13 @@ class CartsControllerTest < ActionDispatch::IntegrationTest
   end
 
   test "should destroy cart" do
+    post line_items_url, params: { product_id: products(:ruby).id }
+    @cart = Cart.find(session[:cart_id])
+
     assert_difference('Cart.count', -1) do
       delete cart_url(@cart)
     end
 
-    assert_redirected_to carts_url
+    assert_redirected_to store_index_url
   end
 end

test/controllers/line_items_controller_test.rb

@@ -22,8 +22,8 @@ class LineItemsControllerTest < ActionDispatch::IntegrationTest
 
     follow_redirect!
 
-    assert_select 'h2', 'Your Pragmatic Cart'
-    assert_select 'li', "1 \u00D7 Programming Ruby 1.9"
+    assert_select 'h2', 'Your Cart'
+    assert_select 'td', 'Programming Ruby 1.9'
   end
 
   test "should show line_item" do