manages focus for assignments/discussion page menus

fixes CNVS-12718

test plan:
 - in a course with 2+ assignment groups
 - once with 1 assignment each, once with 2+ each
 - with draft state on
 - on assignment index page
 - using keyboard navigation for everything
 - click 'move to' for an assignment, close the dialog
 - verify that focus is directed to the settings cog for that assignment
 - repeat for an assignment group
 - click 'delete' for an assignment, click cancel
 - verify that focus is directed to the settings cog
 - click 'delete' for an assignment, click ok
 - for groups with 1 assignment: verify that focus goes to parent assignment group
 - for groups with 2+ assignments: verify that focus goes to previous assignment in list
 - for first assignment in list: verify that focus goes to parent assignment group

 - with draft state on
 - on discussion index page
 - repeat 'move to' and 'delete' verifications from above

Change-Id: I0940b5eed70cecb628c25c597b8439598d096d24
Reviewed-on: https://gerrit.instructure.com/35120
Reviewed-by: Cameron Sutter <csutter@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Aaron Cannon <acannon@instructure.com>

app/coffeescripts/views/DiscussionTopics/DiscussionView.coffee

@@ -59,6 +59,7 @@ define [
       @moveItemView = new MoveDialogView
         model: @model
         nested: true
+        closeTarget: @$el.find('a[id=manage_link]')
         saveURL: -> @model.collection.reorderURL()
       super
 
@@ -88,7 +89,11 @@ define [
     # Returns nothing.
     onDelete: (e) =>
       e.preventDefault()
-      @delete() if confirm(@messages.confirm)
+      if confirm(@messages.confirm)
+        @goToPrevItem()
+        @delete()
+      else
+        @$el.find('a[id=manage_link]').focus()
 
     # Public: Delete the model and update the server.
     #
@@ -97,6 +102,20 @@ define [
       @model.destroy()
       @$el.remove()
 
+    goToPrevItem: =>
+      if @previousDiscussionInGroup()?
+        $('#' + @previousDiscussionInGroup().id + '_discussion_content').attr("tabindex",-1).focus()
+      else if @model.get('pinned')
+        $('.pinned&.discussion-list').attr("tabindex",-1).focus()
+      else if @model.get('locked')
+        $('.locked&.discussion-list').attr("tabindex",-1).focus()
+      else
+        $('.open&.discussion-list').attr("tabindex",-1).focus()
+
+    previousDiscussionInGroup: =>
+      current_index = @model.collection.models.indexOf(@model)
+      @model.collection.models[current_index - 1]
+
     # Public: Pin or unpin the model and update it on the server.
     #
     # e - Event object.

app/coffeescripts/views/MoveDialogView.coffee

@@ -46,6 +46,11 @@ define [
     # required if @nested
     @optionProperty 'childKey'
 
+    # {jQuery selector}
+    # link to focus on after dialog is closed
+    # without taking any action
+    @optionProperty 'closeTarget'
+
     # {string or function}
     # url to post to when saving the form
     #
@@ -104,6 +109,7 @@ define [
       @listView?.remove()
       @parentListView = @listView = null
       @dialog.option "close", null
+      @closeTarget?.focus()
 
     #lookup new collection, and set it on
     #the nested view

app/coffeescripts/views/assignments/AssignmentGroupListItemView.coffee

@@ -120,6 +120,7 @@ define [
           model: @model
         @moveGroupView = new MoveDialogView
           model: @model
+          closeTarget: @$el.find('a[id*=manage_link]')
           saveURL: -> ENV.URLS.sort_url
 
     initCache: ->

app/coffeescripts/views/assignments/AssignmentListItemView.coffee

@@ -76,6 +76,7 @@ define [
           parentLabelText: @messages.ag_move_label
           parentKey: 'assignment_group_id'
           childKey: 'assignments'
+          closeTarget: @$el.find('a[id*=manage_link]')
           saveURL: -> "#{ENV.URLS.assignment_sort_base_url}/#{@parentListView.value()}/reorder"
 
       @dateDueColumnView       = new DateDueColumnView(model: @model)
@@ -158,7 +159,14 @@ define [
 
     onDelete: (e) =>
       e.preventDefault()
-      @delete() if confirm(@messages.confirm)
+      return @$el.find('a[id*=manage_link]').focus() unless confirm(@messages.confirm)
+      if @previousAssignmentInGroup()?
+        @focusOnAssignment(@previousAssignmentInGroup())
+        @delete()
+      else
+        id = @model.attributes.assignment_group_id
+        @delete()
+        @focusOnGroupByID(id)
 
     delete: ->
       @model.destroy()

app/views/jst/DiscussionTopics/discussion.handlebars

@@ -1,4 +1,4 @@
-<div class="discussion-content">
+<div class="discussion-content" id="{{id}}_discussion_content">
   <div class="discussion-row{{#if ENV.permissions.publish}} {{#if published}}discussion-published{{else}}discussion-unpublished{{/if}}{{/if}}">
     {{#if permissions.moderate}}
       <div class="draggable-handle">
@@ -85,7 +85,7 @@
 
     <div class="discussion-actions" role="application">
       {{#if permissions.delete}}
-        <a href="#" class="al-trigger" role="button">
+        <a href="#" class="al-trigger" role="button" id="manage_link">
           <i class="icon-settings"></i><i class="icon-mini-arrow-down"></i>
           <span class="screenreader-only">{{#t "manage"}}Manage{{/t}}</span>
         </a>

spec/coffeescripts/views/assignments/AssignmentListItemViewSpec.coffee

@@ -169,6 +169,7 @@ define [
   test 'asks for confirmation before deleting an assignment', ->
     view = createView(@model)
 
+    group_stub = sinon.stub(view, 'visibleAssignments', -> [])
     confirm_stub = sinon.stub(window, "confirm", -> true )
     delete_spy = sinon.spy view, "delete"
 
@@ -179,6 +180,7 @@ define [
 
     confirm_stub.restore()
     delete_spy.restore()
+    group_stub.restore()
 
   test "delete destroys model", ->
     old_asset_string = ENV.context_asset_string
@@ -277,6 +279,7 @@ define [
     @server.respond()
 
     equal @model.get('published'), true
+    @server.restore()
 
   test "correctly displays module's name", ->
     mods = genModules(1)

spec/coffeescripts/views/external_tools/AddAppViewSpec.coffee

@@ -120,6 +120,7 @@ define [
 
     teardown: ->
       view.remove()
+      server.restore()
 
   test 'AddAppView: render', ->
     equal $.trim($('.ui-dialog-title:visible').text()), "Add App",