Refs issue #12: Add a last name cannot be blank error message

app/controllers/authors_controller.rb

@@ -9,11 +9,16 @@ def show
   end
 
   def new
+    @author = Author.new
   end
+
   def create
     @author = Author.new(author_params)
-    @author.save
-    redirect_to @author
+    if @author.save
+      redirect_to @author
+    else
+      render 'new'
+    end
   end
 
   private

app/models/author.rb

@@ -1,6 +1,5 @@
 class Author < ActiveRecord::Base
-  validates :last_name, presence: true,
-                        length: { minimum: 1 }
+  validates :last_name, presence: true
   def name
     first_name + ' ' + last_name
   end

app/views/authors/new.html.erb

@@ -1,4 +1,19 @@
 <%= form_for :author, url: authors_path do |f| %>
+
+    <% if @author.errors.any? %>
+        <div id="error_explanation">
+          <h2>
+            <%= pluralize(@author.errors.count, "error") %>
+            prohibits the author to be created
+          </h2>
+          <ul>
+            <% @author.errors.full_messages.each do |msg| %>
+                <li><%= msg %></li>
+            <% end %>
+          </ul>
+        </div>
+    <% end %>
+
     <p>
       <%= f.label :first_name %><br>
       <%= f.text_field :first_name %>

spec/features/author/new_author_spec.rb

@@ -33,7 +33,7 @@
 
     find('input[type="submit"]').click
 
-    expect(page).to have_text('last name can\'t be blank')
+    expect(page).to have_text('Last name can\'t be blank')
   end
 
 end