`WikiPage` should have a slug even when not persisted.

app/models/wiki_page.rb

@@ -44,7 +44,11 @@ class WikiPage
 
   # The escaped URL path of this page.
   def slug
-    @attributes[:slug]
+    if @attributes[:slug].present?
+      @attributes[:slug]
+    else
+      wiki.wiki.preview_page(title, '', format).url_path
+    end
   end
 
   alias_method :to_param, :slug

app/views/layouts/project.html.haml

@@ -5,7 +5,7 @@
 
 - content_for :scripts_body_top do
   - project = @target_project || @project
-  - if @project_wiki && @page && @page.slug.present?
+  - if @project_wiki && @page
     - markdown_preview_path = namespace_project_wiki_markdown_preview_path(project.namespace, project, @page.slug)
   - else
     - markdown_preview_path = markdown_preview_namespace_project_path(project.namespace, project)

spec/features/projects/wiki/markdown_preview_spec.rb

+require 'spec_helper'
+
+feature 'Projects > Wiki > User previews markdown changes', feature: true, js: true do
+  let(:user) { create(:user) }
+  let(:project) { create(:project, namespace: user.namespace) }
+  let(:wiki_content) do
+    <<-HEREDOC
+[regular link](regular)
+[relative link 1](../relative)
+[relative link 2](./relative)
+[relative link 3](./e/f/relative)
+    HEREDOC
+  end
+
+  background do
+    project.team << [user, :master]
+    login_as(user)
+
+    visit namespace_project_path(project.namespace, project)
+    click_link 'Wiki'
+    WikiPages::CreateService.new(project, user, title: 'home', content: 'Home page').execute
+  end
+
+  context "while creating a new wiki page" do
+    context "when there are no spaces or hyphens in the page name" do
+      it "rewrites relative links as expected" do
+        click_link 'New Page'
+        fill_in :new_wiki_path, with: 'a/b/c/d'
+        click_button 'Create Page'
+
+        fill_in :wiki_content, with: wiki_content
+        click_on "Preview"
+
+        expect(page).to have_content("regular link")
+
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/regular\">regular link</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a/b/relative\">relative link 1</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a/b/c/relative\">relative link 2</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a/b/c/e/f/relative\">relative link 3</a>")
+      end
+    end
+
+    context "when there are spaces in the page name" do
+      it "rewrites relative links as expected" do
+        click_link 'New Page'
+        fill_in :new_wiki_path, with: 'a page/b page/c page/d page'
+        click_button 'Create Page'
+
+        fill_in :wiki_content, with: wiki_content
+        click_on "Preview"
+
+        expect(page).to have_content("regular link")
+
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/regular\">regular link</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/relative\">relative link 1</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/relative\">relative link 2</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/e/f/relative\">relative link 3</a>")
+      end
+    end
+
+    context "when there are hyphens in the page name" do
+      it "rewrites relative links as expected" do
+        click_link 'New Page'
+        fill_in :new_wiki_path, with: 'a-page/b-page/c-page/d-page'
+        click_button 'Create Page'
+
+        fill_in :wiki_content, with: wiki_content
+        click_on "Preview"
+
+        expect(page).to have_content("regular link")
+
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/regular\">regular link</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/relative\">relative link 1</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/relative\">relative link 2</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/e/f/relative\">relative link 3</a>")
+      end
+    end
+  end
+
+  context "while editing a wiki page" do
+    def create_wiki_page(path)
+      click_link 'New Page'
+      fill_in :new_wiki_path, with: path
+      click_button 'Create Page'
+      fill_in :wiki_content, with: 'content'
+      click_on "Create page"
+    end
+
+    context "when there are no spaces or hyphens in the page name" do
+      it "rewrites relative links as expected" do
+        create_wiki_page 'a/b/c/d'
+        click_link 'Edit'
+
+        fill_in :wiki_content, with: wiki_content
+        click_on "Preview"
+
+        expect(page).to have_content("regular link")
+
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/regular\">regular link</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a/b/relative\">relative link 1</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a/b/c/relative\">relative link 2</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a/b/c/e/f/relative\">relative link 3</a>")
+      end
+    end
+
+    context "when there are spaces in the page name" do
+      it "rewrites relative links as expected" do
+        create_wiki_page 'a page/b page/c page/d page'
+        click_link 'Edit'
+
+        fill_in :wiki_content, with: wiki_content
+        click_on "Preview"
+
+        expect(page).to have_content("regular link")
+
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/regular\">regular link</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/relative\">relative link 1</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/relative\">relative link 2</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/e/f/relative\">relative link 3</a>")
+      end
+    end
+
+    context "when there are hyphens in the page name" do
+      it "rewrites relative links as expected" do
+        create_wiki_page 'a-page/b-page/c-page/d-page'
+        click_link 'Edit'
+
+        fill_in :wiki_content, with: wiki_content
+        click_on "Preview"
+
+        expect(page).to have_content("regular link")
+
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/regular\">regular link</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/relative\">relative link 1</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/relative\">relative link 2</a>")
+        expect(page.html).to include("<a href=\"/#{project.path_with_namespace}/wikis/a-page/b-page/c-page/e/f/relative\">relative link 3</a>")
+      end
+    end
+  end
+end

spec/features/projects/wiki/user_creates_wiki_page_spec.rb

@@ -30,18 +30,48 @@ feature 'Projects > Wiki > User creates wiki page', feature: true do
         WikiPages::CreateService.new(project, user, title: 'home', content: 'Home page').execute
       end
 
-      scenario 'via the "new wiki page" page', js: true do
-        click_link 'New Page'
+      context 'via the "new wiki page" page' do
+        scenario 'when the wiki page has a single word name', js: true do
+          click_link 'New Page'
 
-        fill_in :new_wiki_path, with: 'foo'
-        click_button 'Create Page'
+          fill_in :new_wiki_path, with: 'foo'
+          click_button 'Create Page'
 
-        fill_in :wiki_content, with: 'My awesome wiki!'
-        click_button 'Create page'
+          fill_in :wiki_content, with: 'My awesome wiki!'
+          click_button 'Create page'
 
-        expect(page).to have_content('Foo')
-        expect(page).to have_content("last edited by #{user.name}")
-        expect(page).to have_content('My awesome wiki!')
+          expect(page).to have_content('Foo')
+          expect(page).to have_content("last edited by #{user.name}")
+          expect(page).to have_content('My awesome wiki!')
+        end
+
+        scenario 'when the wiki page has spaces in the name', js: true do
+          click_link 'New Page'
+
+          fill_in :new_wiki_path, with: 'Spaces in the name'
+          click_button 'Create Page'
+
+          fill_in :wiki_content, with: 'My awesome wiki!'
+          click_button 'Create page'
+
+          expect(page).to have_content('Spaces in the name')
+          expect(page).to have_content("last edited by #{user.name}")
+          expect(page).to have_content('My awesome wiki!')
+        end
+
+        scenario 'when the wiki page has hyphens in the name', js: true do
+          click_link 'New Page'
+
+          fill_in :new_wiki_path, with: 'hyphens-in-the-name'
+          click_button 'Create Page'
+
+          fill_in :wiki_content, with: 'My awesome wiki!'
+          click_button 'Create page'
+
+          expect(page).to have_content('Hyphens in the name')
+          expect(page).to have_content("last edited by #{user.name}")
+          expect(page).to have_content('My awesome wiki!')
+        end
       end
     end
   end