modifications to Backbone textbook structure

Textbooks now have an empty chapterset by default, instead of one with one empty
chapter. The TextbookEdit view dynamically adds an empty chapter if the chapterset
is empty; the close button removes all empty chapters from the chapterset.

cms/static/coffee/spec/views/textbook_spec.coffee

@@ -89,10 +89,18 @@ describe "CMS.Views.TextbookEdit", ->
             @view.render()
             expect(@view.$("input[name=textbook-name]").val()).toEqual("Life Sciences")
 
-        it "should allow you to create new chapters", ->
+        it "should create an empty chapter when it is rendered, if there are no chapters", ->
+            expect(@model.get("chapters").length).toEqual(0)
+            @view.render()
+            expect(@model.get("chapters").length).toEqual(1)
+            expect(@model.get("chapters").last().isEmpty()).toBeTruthy()
+
+        it "should allow you to create new empty chapters", ->
+            @view.render()
             numChapters = @model.get("chapters").length
-            @view.render().$(".action-add-chapter").click()
+            @view.$(".action-add-chapter").click()
             expect(@model.get("chapters").length).toEqual(numChapters+1)
+            expect(@model.get("chapters").last().isEmpty()).toBeTruthy()
 
         it "should save properly", ->
             @view.render()
@@ -104,6 +112,7 @@ describe "CMS.Views.TextbookEdit", ->
             expect(@collection.save).toHaveBeenCalled()
 
         it "does not save on cancel", ->
+            @model.get("chapters").add([{name: "a", asset_path: "b"}])
             @view.render()
             @view.$("input[name=textbook-name]").val("starfish")
             @view.$("input[name=chapter1-name]").val("foobar")
@@ -113,6 +122,14 @@ describe "CMS.Views.TextbookEdit", ->
             expect(@collection.save).not.toHaveBeenCalled()
             expect(@collection.editing).toBeUndefined()
 
+        it "does not save empty chapters on cancel", ->
+            chapters = @model.get("chapters")
+            origLength = chapters.length
+            @view.render()
+            chapters.add([{}, {}, {}]) # add three empty chapters
+            @view.$(".action-cancel").click()
+            expect(chapters.length).toEqual(origLength)
+
 
 describe "CMS.Views.ListTextbooks", ->
     noTextbooksTpl = readFixtures("no-textbooks.underscore")