Wiki page hierarchy (#528). Parent page can be assigned on Rename screen.

git-svn-id: http://redmine.rubyforge.org/svn/trunk@1698 e93f8b46-1217-0410-a6f0-8f06a7374b81

38 files changed, 139 insertions, 11 deletions

diff --git a/app/controllers/wiki_controller.rb b/app/controllers/wiki_controller.rb
index 8655cfed7..2430205cf 100644
--- a/app/controllers/wiki_controller.rb
+++ b/app/controllers/wiki_controller.rb
@@ -147,6 +147,7 @@ class WikiController < ApplicationController
                                       :joins => "LEFT JOIN #{WikiContent.table_name} ON #{WikiContent.table_name}.page_id = #{WikiPage.table_name}.id",
                                       :order => 'title'
       @pages_by_date = @pages.group_by {|p| p.updated_on.to_date}
+      @pages_by_parent_id = @pages.group_by(&:parent_id)
     # export wiki to a single html file
     when 'export'
       @pages = @wiki.pages.find :all, :order => 'title'
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 7bcec461e..f5ce7ecda 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -177,7 +177,8 @@ module ApplicationHelper
   end
   
   def breadcrumb(*args)
-    content_tag('p', args.join(' &#187; ') + ' &#187; ', :class => 'breadcrumb')
+    elements = args.flatten
+    elements.any? ? content_tag('p', args.join(' &#187; ') + ' &#187; ', :class => 'breadcrumb') : nil
   end
   
   def html_title(*args)
diff --git a/app/helpers/wiki_helper.rb b/app/helpers/wiki_helper.rb
index 980035bd4..d27ce3ea3 100644
--- a/app/helpers/wiki_helper.rb
+++ b/app/helpers/wiki_helper.rb
@@ -17,6 +17,22 @@
 
 module WikiHelper
 
+  def render_page_hierarchy(pages, node=nil)
+    content = ''
+    if pages[node]
+      content << "<ul class=\"pages-hierarchy\">\n"
+      pages[node].each do |page|
+        content << "<li>"
+        content << link_to(h(page.pretty_title), {:action => 'index', :page => page.title},
+                           :title => l(:label_updated_time, distance_of_time_in_words(Time.now, page.updated_on)))
+        content << "\n" + render_page_hierarchy(pages, page.id) if pages[page.id]
+        content << "</li>\n"
+      end
+      content << "</ul>\n"
+    end
+    content
+  end
+  
   def html_diff(wdiff)
     words = wdiff.words.collect{|word| h(word)}
     words_add = 0
diff --git a/app/models/wiki_page.rb b/app/models/wiki_page.rb
index 65fc1f68c..2416fab74 100644
--- a/app/models/wiki_page.rb
+++ b/app/models/wiki_page.rb
@@ -22,7 +22,8 @@ class WikiPage < ActiveRecord::Base
   belongs_to :wiki
   has_one :content, :class_name => 'WikiContent', :foreign_key => 'page_id', :dependent => :destroy
   has_many :attachments, :as => :container, :dependent => :destroy
-
+  acts_as_tree :order => 'title'
+  
   acts_as_event :title => Proc.new {|o| "#{l(:label_wiki)}: #{o.title}"},
                 :description => :text,
                 :datetime => :created_on,
@@ -110,6 +111,24 @@ class WikiPage < ActiveRecord::Base
   def editable_by?(usr)
     !protected? || usr.allowed_to?(:protect_wiki_pages, wiki.project)
   end
+  
+  def parent_title
+    @parent_title || (self.parent && self.parent.pretty_title)
+  end
+  
+  def parent_title=(t)
+    @parent_title = t
+    parent_page = t.blank? ? nil : self.wiki.find_page(t)
+    self.parent = parent_page
+  end
+  
+  protected
+  
+  def validate
+    errors.add(:parent_title, :activerecord_error_invalid) if !@parent_title.blank? && parent.nil?
+    errors.add(:parent_title, :activerecord_error_circular_dependency) if parent && (parent == self || parent.ancestors.include?(self))
+    errors.add(:parent_title, :activerecord_error_not_same_project) if parent && (parent.wiki_id != wiki_id)
+  end
 end
 
 class WikiDiff
diff --git a/app/views/wiki/rename.rhtml b/app/views/wiki/rename.rhtml
index 0c069f43d..260f9af8b 100644
--- a/app/views/wiki/rename.rhtml
+++ b/app/views/wiki/rename.rhtml
@@ -4,8 +4,9 @@
 
 <% labelled_tabular_form_for :wiki_page, @page, :url => { :action => 'rename' } do |f| %>
 <div class="box">
-<p><%= f.text_field :title, :required => true, :size => 255  %></p>
+<p><%= f.text_field :title, :required => true, :size => 100  %></p>
 <p><%= f.check_box :redirect_existing_links %></p>
+<p><%= f.text_field :parent_title, :size => 100  %></p>
 </div>
 <%= submit_tag l(:button_rename) %>
 <% end %>
diff --git a/app/views/wiki/show.rhtml b/app/views/wiki/show.rhtml
index 8092525bd..255b904f5 100644
--- a/app/views/wiki/show.rhtml
+++ b/app/views/wiki/show.rhtml
@@ -10,6 +10,8 @@
 <%= link_to(l(:label_history), {:action => 'history', :page => @page.title}, :class => 'icon icon-history') %>
 </div>
 
+<%= breadcrumb(@page.ancestors.reverse.collect {|parent| link_to h(parent.pretty_title), {:page => parent.title}}) %>
+
 <% if @content.version != @page.content.version %>
     <p>    
     <%= link_to(('&#171; ' + l(:label_previous)), :action => 'index', :page => @page.title, :version => (@content.version - 1)) + " - " if @content.version > 1 %>
diff --git a/app/views/wiki/special_page_index.rhtml b/app/views/wiki/special_page_index.rhtml
index f21cc3423..72b395ef7 100644
--- a/app/views/wiki/special_page_index.rhtml
+++ b/app/views/wiki/special_page_index.rhtml
@@ -4,11 +4,7 @@
 <p class="nodata"><%= l(:label_no_data) %></p>
 <% end %>
 
-<ul><% @pages.each do |page| %>
-    <li><%= link_to page.pretty_title, {:action => 'index', :page => page.title},
-                                       :title => l(:label_updated_time, distance_of_time_in_words(Time.now, page.updated_on)) %>
-    </li>
-<% end %></ul>
+<%= render_page_hierarchy(@pages_by_parent_id) %>
 
 <% content_for :sidebar do %>
   <%= render :partial => 'sidebar' %>
diff --git a/db/migrate/095_add_wiki_pages_parent_id.rb b/db/migrate/095_add_wiki_pages_parent_id.rb
new file mode 100644
index 000000000..36b922ec1
--- /dev/null
+++ b/db/migrate/095_add_wiki_pages_parent_id.rb
@@ -0,0 +1,9 @@
+class AddWikiPagesParentId < ActiveRecord::Migration
+  def self.up
+    add_column :wiki_pages, :parent_id, :integer, :default => nil
+  end
+
+  def self.down
+    remove_column :wiki_pages, :parent_id
+  end
+end
diff --git a/lang/bg.yml b/lang/bg.yml
index c87e3bebc..e8191dc20 100644
--- a/lang/bg.yml
+++ b/lang/bg.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/cs.yml b/lang/cs.yml
index 6669c6cf3..68273191a 100644
--- a/lang/cs.yml
+++ b/lang/cs.yml
@@ -637,3 +637,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/da.yml b/lang/da.yml
index cf40e1763..1b5aba69c 100644
--- a/lang/da.yml
+++ b/lang/da.yml
@@ -634,3 +634,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/de.yml b/lang/de.yml
index adc3dd4e9..dc2960c9c 100644
--- a/lang/de.yml
+++ b/lang/de.yml
@@ -633,3 +633,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/en.yml b/lang/en.yml
index 791094674..3cc788b8c 100644
--- a/lang/en.yml
+++ b/lang/en.yml
@@ -182,6 +182,7 @@ field_time_zone: Time zone
 field_searchable: Searchable
 field_default_value: Default value
 field_comments_sorting: Display comments
+field_parent_title: Parent page
 
 setting_app_title: Application title
 setting_app_subtitle: Application subtitle
diff --git a/lang/es.yml b/lang/es.yml
index 4205402e4..c753f367f 100644
--- a/lang/es.yml
+++ b/lang/es.yml
@@ -635,3 +635,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/fi.yml b/lang/fi.yml
index b69b07557..b48d8a319 100644
--- a/lang/fi.yml
+++ b/lang/fi.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/fr.yml b/lang/fr.yml
index 5b0f04fb0..b9d542da6 100644
--- a/lang/fr.yml
+++ b/lang/fr.yml
@@ -183,6 +183,7 @@ field_time_zone: Fuseau horaire
 field_searchable: Utilisé pour les recherches
 field_default_value: Valeur par défaut
 field_comments_sorting: Afficher les commentaires
+field_parent_title: Page parent
 
 setting_app_title: Titre de l'application
 setting_app_subtitle: Sous-titre de l'application
diff --git a/lang/he.yml b/lang/he.yml
index 030e09dcc..63aa2bb64 100644
--- a/lang/he.yml
+++ b/lang/he.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/hu.yml b/lang/hu.yml
index 630294c9d..9becbb349 100644
--- a/lang/hu.yml
+++ b/lang/hu.yml
@@ -633,3 +633,4 @@ label_generate_key: Kulcs generálása
 setting_mail_handler_api_enabled: Web Service engedélyezése a beérkezett levelekhez
 setting_mail_handler_api_key: API kulcs
 text_email_delivery_not_configured: "Az E-mail küldés nincs konfigurálva, és az értesítések ki vannak kapcsolva.\nÁllítsd be az SMTP szervert a config/email.yml fájlban és indítsd újra az alkalmazást, hogy érvénybe lépjen."
+field_parent_title: Parent page
diff --git a/lang/it.yml b/lang/it.yml
index 471ef49ed..e7a8772cc 100644
--- a/lang/it.yml
+++ b/lang/it.yml
@@ -632,3 +632,4 @@ label_generate_key: Genera una chiave
 setting_mail_handler_api_enabled: Abilita WS per le e-mail in arrivo
 setting_mail_handler_api_key: chiave API
 text_email_delivery_not_configured: "La consegna via e-mail non è configurata e le notifiche sono disabilitate.\nConfigura il tuo server SMTP in config/email.yml e riavvia l'applicazione per abilitarle."
+field_parent_title: Parent page
diff --git a/lang/ja.yml b/lang/ja.yml
index cba410f6d..f78fcdba4 100644
--- a/lang/ja.yml
+++ b/lang/ja.yml
@@ -633,3 +633,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/ko.yml b/lang/ko.yml
index 2b5b0eb0a..77672c601 100644
--- a/lang/ko.yml
+++ b/lang/ko.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/lt.yml b/lang/lt.yml
index 52b6b6fc8..706133bfe 100644
--- a/lang/lt.yml
+++ b/lang/lt.yml
@@ -635,3 +635,4 @@ setting_mail_handler_api_enabled: Įgalinti WS įeinantiems laiškams
 setting_mail_handler_api_key: API raktas
 
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/nl.yml b/lang/nl.yml
index 09cdc3c08..3cfb0aa19 100644
--- a/lang/nl.yml
+++ b/lang/nl.yml
@@ -633,3 +633,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/no.yml b/lang/no.yml
index eb1ff59ca..0836bd48f 100644
--- a/lang/no.yml
+++ b/lang/no.yml
@@ -633,3 +633,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/pl.yml b/lang/pl.yml
index 9c5a382b0..278d56a88 100644
--- a/lang/pl.yml
+++ b/lang/pl.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/pt-br.yml b/lang/pt-br.yml
index 1582e568f..9276d768e 100644
--- a/lang/pt-br.yml
+++ b/lang/pt-br.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails

 setting_mail_handler_api_key: API key

 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."

+field_parent_title: Parent page

diff --git a/lang/pt.yml b/lang/pt.yml
index ece12cd97..a7647e31f 100644
--- a/lang/pt.yml
+++ b/lang/pt.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/ro.yml b/lang/ro.yml
index 50bbf29af..c3640d7e1 100644
--- a/lang/ro.yml
+++ b/lang/ro.yml
@@ -632,3 +632,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/ru.yml b/lang/ru.yml
index c0cac30a0..e8bda05b7 100644
--- a/lang/ru.yml
+++ b/lang/ru.yml
@@ -636,3 +636,4 @@ label_generate_key: Сгенерировать ключ
 setting_mail_handler_api_enabled: Включить веб-сервис для входящих сообщений
 setting_mail_handler_api_key: API ключ
 text_email_delivery_not_configured: "Параметры работы с почтовым сервером не настроены и функция уведомления по email не активна.\nНастроить параметры для вашего SMTP сервера вы можете в файле config/email.yml. Для применения изменений перезапустите приложение."
+field_parent_title: Parent page
diff --git a/lang/sr.yml b/lang/sr.yml
index fa1b4d847..688fa8ede 100644
--- a/lang/sr.yml
+++ b/lang/sr.yml
@@ -633,3 +633,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/sv.yml b/lang/sv.yml
index 9015099e7..58507a0b7 100644
--- a/lang/sv.yml
+++ b/lang/sv.yml
@@ -633,3 +633,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/th.yml b/lang/th.yml
index 27f7b14cf..a7f949c96 100644
--- a/lang/th.yml
+++ b/lang/th.yml
@@ -635,3 +635,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/uk.yml b/lang/uk.yml
index 0286779be..766ddaaab 100644
--- a/lang/uk.yml
+++ b/lang/uk.yml
@@ -634,3 +634,4 @@ label_generate_key: Generate a key
 setting_mail_handler_api_enabled: Enable WS for incoming emails
 setting_mail_handler_api_key: API key
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/lang/zh-tw.yml b/lang/zh-tw.yml
index bad6fcca5..82f26ab86 100644
--- a/lang/zh-tw.yml
+++ b/lang/zh-tw.yml
@@ -633,3 +633,4 @@ default_activity_development: 開發
 enumeration_issue_priorities: 項目優先權
 enumeration_doc_categories: 文件分類
 enumeration_activities: 活動 (時間追蹤)
+field_parent_title: Parent page
diff --git a/lang/zh.yml b/lang/zh.yml
index 1cde9f502..b4ae89ba7 100644
--- a/lang/zh.yml
+++ b/lang/zh.yml
@@ -633,3 +633,4 @@ enumeration_issue_priorities: 问题优先级
 enumeration_doc_categories: 文档类别
 enumeration_activities: 活动（时间跟踪）
 text_email_delivery_not_configured: "Email delivery is not configured, and notifications are disabled.\nConfigure your SMTP server in config/email.yml and restart the application to enable them."
+field_parent_title: Parent page
diff --git a/test/fixtures/wiki_pages.yml b/test/fixtures/wiki_pages.yml
index ef7242430..e285441ff 100644
--- a/test/fixtures/wiki_pages.yml
+++ b/test/fixtures/wiki_pages.yml
@@ -4,23 +4,27 @@ wiki_pages_001:
   title: CookBook_documentation

   id: 1

   wiki_id: 1

-  protected: true  

+  protected: true

+  parent_id: 

 wiki_pages_002: 

   created_on: 2007-03-08 00:18:07 +01:00

   title: Another_page

   id: 2

   wiki_id: 1

   protected: false

+  parent_id: 

 wiki_pages_003: 

   created_on: 2007-03-08 00:18:07 +01:00

   title: Start_page

   id: 3

   wiki_id: 2

   protected: false

+  parent_id: 

 wiki_pages_004: 

   created_on: 2007-03-08 00:18:07 +01:00

   title: Page_with_an_inline_image

   id: 4

   wiki_id: 1

   protected: false

+  parent_id: 1

   
\ No newline at end of file
diff --git a/test/functional/wiki_controller_test.rb b/test/functional/wiki_controller_test.rb
index f1ae7a9c2..06d8cacf2 100644
--- a/test/functional/wiki_controller_test.rb
+++ b/test/functional/wiki_controller_test.rb
@@ -163,8 +163,16 @@ class WikiControllerTest < Test::Unit::TestCase
     pages = assigns(:pages)
     assert_not_nil pages
     assert_equal Project.find(1).wiki.pages.size, pages.size
-    assert_tag :tag => 'a', :attributes => { :href => '/wiki/ecookbook/CookBook_documentation' },
-                            :content => /CookBook documentation/
+    
+    assert_tag :ul, :attributes => { :class => 'pages-hierarchy' },
+                    :child => { :tag => 'li', :child => { :tag => 'a', :attributes => { :href => '/wiki/ecookbook/CookBook_documentation' },
+                                              :content => 'CookBook documentation' },
+                                :child => { :tag => 'ul',
+                                            :child => { :tag => 'li',
+                                                        :child => { :tag => 'a', :attributes => { :href => '/wiki/ecookbook/Page_with_an_inline_image' },
+                                                                                 :content => 'Page with an inline image' } } } },
+                    :child => { :tag => 'li', :child => { :tag => 'a', :attributes => { :href => '/wiki/ecookbook/Another_page' },
+                                                                       :content => 'Another page' } }
   end
   
   def test_not_found
diff --git a/test/unit/wiki_page_test.rb b/test/unit/wiki_page_test.rb
index bb8111176..e5ebeeea6 100644
--- a/test/unit/wiki_page_test.rb
+++ b/test/unit/wiki_page_test.rb
@@ -48,6 +48,50 @@ class WikiPageTest < Test::Unit::TestCase
     assert page.new_record?
   end
   
+  def test_parent_title
+    page = WikiPage.find_by_title('Another_page')
+    assert_nil page.parent_title
+    
+    page = WikiPage.find_by_title('Page_with_an_inline_image')
+    assert_equal 'CookBook documentation', page.parent_title
+  end
+  
+  def test_assign_parent
+    page = WikiPage.find_by_title('Another_page')
+    page.parent_title = 'CookBook documentation'
+    assert page.save
+    page.reload
+    assert_equal WikiPage.find_by_title('CookBook_documentation'), page.parent
+  end
+  
+  def test_unassign_parent
+    page = WikiPage.find_by_title('Page_with_an_inline_image')
+    page.parent_title = ''
+    assert page.save
+    page.reload
+    assert_nil page.parent
+  end
+  
+  def test_parent_validation
+    page = WikiPage.find_by_title('CookBook_documentation')
+    
+    # A page that doesn't exist
+    page.parent_title = 'Unknown title'
+    assert !page.save
+    assert_equal :activerecord_error_invalid, page.errors.on(:parent_title)
+    # A child page
+    page.parent_title = 'Page_with_an_inline_image'
+    assert !page.save
+    assert_equal :activerecord_error_circular_dependency, page.errors.on(:parent_title)
+    # The page itself
+    page.parent_title = 'CookBook_documentation'
+    assert !page.save
+    assert_equal :activerecord_error_circular_dependency, page.errors.on(:parent_title)
+
+    page.parent_title = 'Another_page'
+    assert page.save
+  end
+  
   def test_destroy
     page = WikiPage.find(1)
     page.destroy