fix publishing wiki page after renaming on modules page

test plan:
 - have a module with an unpublished wiki page
 - from the modules page, rename the wiki page via the gear menu
   and "edit" item
 - without reloading the page, click the cloud icon to publish
   the wiki page
 - go to the Pages tab and ensure only the new name appears
   (publishing the page didn't create a new published page with
    the old name, leaving the renamed page unpublished)

fixes CNVS-18693

Change-Id: I1a1995f81dfe1d02cebc558bbaee716e930c8354
Reviewed-on: https://gerrit.instructure.com/49593
Tested-by: Jenkins
QA-Review: Jahnavi Yetukuri <jyetukuri@instructure.com>
Reviewed-by: James Williams  <jamesw@instructure.com>
Product-Review: Jeremy Stanley <jeremy@instructure.com>

Author: jstanley0

app/helpers/context_modules_helper.rb

@@ -41,7 +41,7 @@ def module_item_publishable_id(item)
     if item.nil?
       ''
     elsif (item.content_type_class == 'wiki_page')
-      item.content.url
+      "page_id:#{item.content.id}"
     else
       (item.content && item.content.respond_to?(:published?) ? item.content.id : item.id)
     end

app/models/wiki.rb

@@ -189,6 +189,9 @@ def build_wiki_page(user, opts={})
   end
 
   def find_page(param)
+    if (match = param.match(/\Apage_id:(\d+)\z/))
+      return self.wiki_pages.where(id: match[1].to_i).first
+    end
     self.wiki_pages.not_deleted.where(url: param.to_s).first ||
       self.wiki_pages.not_deleted.where(url: param.to_url).first ||
       self.wiki_pages.not_deleted.where(id: param.to_i).first

spec/selenium/context_modules_spec.rb

@@ -380,6 +380,30 @@ def test_relock
       @assignment.context_module_tags.each { |tag| expect(tag.title).to eq 'again' }
     end
 
+    it "should not create a duplicate page if you publish after renaming" do
+      mod = @course.context_modules.create! name: 'TestModule'
+      page = @course.wiki.wiki_pages.create title: 'A Page'
+      page.workflow_state = 'unpublished'
+      page.save!
+      page_count = @course.wiki.wiki_pages.count
+      tag = mod.add_item({:id => page.id, :type => 'wiki_page'})
+
+      get "/courses/#{@course.id}/modules"
+      wait_for_modules_ui
+
+      item = f("#context_module_item_#{tag.id}")
+      edit_module_item(item) do |edit_form|
+        replace_content(edit_form.find_element(:id, 'content_tag_title'), 'Renamed!')
+      end
+
+      item = f("#context_module_item_#{tag.id}")
+      item.find_element(:css, '.publish-icon').click
+      wait_for_ajax_requests
+
+      expect(@course.wiki.wiki_pages.count).to eq page_count
+      expect(page.reload).to be_published
+    end
+
     it "should add the 'with-completion-requirements' class to rows that have requirements" do
       mod = @course.context_modules.create! name: 'TestModule'
       tag = mod.add_item({:id => @assignment.id, :type => 'assignment'})