Add cohort selector tests in forum NewPostView

common/static/coffee/spec/discussion/discussion_spec_helper.coffee

@@ -38,6 +38,13 @@ class @DiscussionSpecHelper
             is_cohorted: is_cohorted
         )
 
+    @makeAjaxSpy = (fakeAjax) ->
+        spyOn($, "ajax").andCallFake(
+            (params) ->
+                fakeAjax(params)
+                {always: ->}
+        )
+
     @setUnderscoreFixtures = ->
         for templateName in ['thread-show']
             templateFixture = readFixtures('templates/discussion/' + templateName + '.underscore')

common/static/coffee/spec/discussion/view/new_post_view_spec.coffee

@@ -204,6 +204,58 @@ describe "NewPostView", ->
           checkPostCancelReset(mode, @discussion, @course_settings)
       )
 
+    describe "cohort selector", ->
+      beforeEach ->
+        @course_settings = new DiscussionCourseSettings({
+          "category_map": {
+            "children": ["Topic"],
+            "entries": {"Topic": {"is_cohorted": true, "id": "topic"}}
+          },
+          "allow_anonymous": false,
+          "allow_anonymous_to_peers": false,
+          "is_cohorted": true,
+          "cohorts": [
+            {"id": 1, "name": "Cohort1"},
+            {"id": 2, "name": "Cohort2"}
+          ]
+        })
+        @view = new NewPostView(
+          el: $("#fixture-element"),
+          collection: @discussion,
+          course_settings: @course_settings,
+          mode: "tab"
+        )
+
+      expectCohortSelectorVisible = (view, visible) ->
+        expect(view.$(".js-group-select").is(":visible")).toEqual(visible)
+
+      it "is not visible to students", ->
+        @view.render()
+        expectCohortSelectorVisible(@view, false)
+
+      it "allows moderators to select visibility", ->
+        DiscussionSpecHelper.makeModerator()
+        @view.render()
+        expectCohortSelectorVisible(@view, true)
+        expect(@view.$(".js-group-select").prop("disabled")).toEqual(false)
+
+        expectedGroupId = null
+        DiscussionSpecHelper.makeAjaxSpy(
+          (params) -> expect(params.data.group_id).toEqual(expectedGroupId)
+        )
+
+        _.each(
+          ["1", "2", ""],
+          (groupIdStr) =>
+            expectedGroupId = groupIdStr
+            @view.$(".js-group-select").val(groupIdStr)
+            @view.$(".js-post-title").val("dummy title")
+            @view.$(".js-post-body textarea").val("dummy body")
+            @view.$(".forum-new-post-form").submit()
+            expect($.ajax).toHaveBeenCalled()
+            $.ajax.reset()
+        )
+
     it "posts to the correct URL", ->
       topicId = "test_topic"
       spyOn($, "ajax").andCallFake(