Review notes:

 * Extracted common template parts in index.html and discussion_course into standalone template file
 * Improved discussion router test, so now it actually tests loading thread not in collection

common/static/coffee/spec/discussion/discussion_router_spec.coffee

@@ -132,6 +132,33 @@ describe 'DiscussionRouter', ->
       }),
     ]
 
+    @other_threads = {
+      '12': DiscussionViewSpecHelper.makeThreadWithProps({
+        id: "12",
+        title: "Thread12",
+        votes: {up_count: '74'},
+        comments_count: 0,
+        pinned: false,
+        created_at: '2015-04-03T20:05:39Z',
+      }),
+      '15': DiscussionViewSpecHelper.makeThreadWithProps({
+        id: "15",
+        title: "Thread15",
+        votes: {up_count: '92'},
+        comments_count: 0,
+        pinned: true,
+        created_at: '2015-05-01T19:4:03Z',
+      }),
+      '112': DiscussionViewSpecHelper.makeThreadWithProps({
+        id: "112",
+        title: "Thread112",
+        votes: {up_count: '1'},
+        comments_count: 2,
+        pinned: false,
+        created_at: '2015-06-09T20:05:39Z',
+      })
+    }
+
     spyOn(DiscussionUtil, 'makeWmdEditor')
     @discussion = new Discussion(_.map(@threads, (thread_spec) -> new Thread(thread_spec)), {pages: 2, sort: 'date'})
     @course_settings = new DiscussionCourseSettings({
@@ -159,23 +186,27 @@ describe 'DiscussionRouter', ->
         spyOn(@router, 'renderThreadView')
         # precondition check - thread is in router's collection
         expect(@router.discussion.get(thread_id)).not.toBeUndefined()
+
         @router.showThread("irrelevant forum name", thread_id)
         expect($.ajax).not.toHaveBeenCalled()
         expect(@router.renderThreadView).toHaveBeenCalled()
+        expect(@router.thread.id).toBe(thread_id)
 
     missingCheck = (forum_name, thread_id) ->
       it "requests thread #{thread_id} in forum #{forum_name} if not already in collection", ->
 
         DiscussionSpecHelper.makeAjaxSpy(
-          (params) -> expect(params.url.path()).toBe(DiscussionUtil.urlFor('retrieve_single_thread', forum_name, thread_id))
+          (params) =>
+            expect(params.url.path()).toBe(DiscussionUtil.urlFor('retrieve_single_thread', forum_name, thread_id))
+            params.success({content: @other_threads[thread_id]})
         )
         spyOn(@router, 'renderThreadView')
-        # precondition check - thread is in router's collection
+        # precondition check - thread is not in router's collection
         expect(@router.discussion.get(thread_id)).toBeUndefined()
+
         @router.showThread(forum_name, thread_id)
-        # in this case showThread makes a hidden async ajax request - it's hard to hook inot it, so it's simpler and
-        # sufficient to just schedule assertion to run as soon as possible, but not immediately
-        setTimeout (() -> expect(@router.renderThreadView).toHaveBeenCalled()), 0
+        expect(@router.renderThreadView).toHaveBeenCalled()
+        expect(@router.thread.id).toBe(thread_id)
 
 
     existingCheck('1')

common/templates/discussion/_course_discussion_section.html

+<section class="discussion container" id="discussion-container"
+       data-roles="${roles}"
+       data-course-id="${course_id}"
+       data-user-info="${user_info}"
+       data-threads="${threads}"
+       data-thread-pages="${thread_pages}"
+       data-content-info="${annotated_content_info}"
+       data-sort-preference="${sort_preference}"
+       data-flag-moderator="${flag_moderator}"
+       data-user-cohort-id="${user_cohort}"
+       data-course-settings="${course_settings}">
+<div class="discussion-body">
+  <div class="forum-nav"></div>
+  <div class="discussion-column">
+    <article class="new-post-article" style="display: none"></article>
+    <div class="forum-content"></div>
+  </div>
+</div>
+</section>
+
+<%include file="_underscore_templates.html" />
+<%include file="_thread_list_template.html" />
\ No newline at end of file

common/templates/discussion/_discussion_course.html

@@ -21,27 +21,6 @@
   <div style="display: block; clear: both; height: 1px;"></div>
   % endif
 
-  <section class="discussion container" id="discussion-container"
-           data-roles="${roles}"
-           data-course-id="${course_id}"
-           data-user-info="${user_info}"
-           data-threads="${threads}"
-           data-thread-pages="${thread_pages}"
-           data-content-info="${annotated_content_info}"
-           data-sort-preference="${sort_preference}"
-           data-flag-moderator="${flag_moderator}"
-           data-user-cohort-id="${user_cohort}"
-           data-course-settings="${course_settings}">
-    <div class="discussion-body">
-      <div class="forum-nav"></div>
-      <div class="discussion-column">
-        <article class="new-post-article" style="display: none"></article>
-        <div class="forum-content"></div>
-      </div>
-    </div>
-  </section>
-
-  <%include file="_underscore_templates.html" />
-  <%include file="_thread_list_template.html" />
+  <%include file="_course_discussion_section.html" />
 
 </div>

common/templates/discussion/index.html

@@ -30,25 +30,4 @@
 
 <%include file="_discussion_course_navigation.html" args="active_page='discussion'" />
 
-<section class="discussion container" id="discussion-container"
-         data-roles="${roles}"
-         data-course-id="${course_id | h}"
-         data-user-info="${user_info}"
-         data-threads="${threads}"
-         data-thread-pages="${thread_pages}"
-         data-content-info="${annotated_content_info}"
-         data-sort-preference="${sort_preference}"
-         data-flag-moderator="${flag_moderator}"
-         data-user-cohort-id="${user_cohort}"
-         data-course-settings="${course_settings}">
-    <div class="discussion-body">
-        <div class="forum-nav"></div>
-        <div class="discussion-column">
-          <article class="new-post-article" style="display: none"></article>
-          <div class="forum-content"></div>
-        </div>
-    </div>
-</section>
-
-<%include file="_underscore_templates.html" />
-<%include file="_thread_list_template.html" />
+<%include file="_course_discussion_section.html" />