PDF textbooks only accept PDF files

All other file types will trigger a validation error

cms/static/coffee/spec/models/textbook_spec.coffee

@@ -133,3 +133,26 @@ describe "CMS.Collections.ChapterSet", ->
         # try going back one
         @collection.remove(@collection.last())
         expect(@collection.nextOrder()).toEqual(2)
+
+
+describe "CMS.Models.FileUpload", ->
+    beforeEach ->
+        @model = new CMS.Models.FileUpload()
+
+    it "is valid by default", ->
+        expect(@model.isValid()).toBeTruthy()
+
+    it "is valid for PDF files", ->
+        file = {"type": "application/pdf"}
+        @model.set("selectedFile", file);
+        expect(@model.isValid()).toBeTruthy()
+
+    it "is invalid for text files", ->
+        file = {"type": "text/plain"}
+        @model.set("selectedFile", file);
+        expect(@model.isValid()).toBeFalsy()
+
+    it "is invalid for PNG files", ->
+        file = {"type": "image/png"}
+        @model.set("selectedFile", file);
+        expect(@model.isValid()).toBeFalsy()

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

@@ -230,12 +230,25 @@ describe "CMS.Views.UploadDialog", ->
         expect(@view.$el).toContain("input[type=file]")
         expect(@view.$(".action-upload")).toBeDisabled()
 
-    it "should render with a file selected", ->
-        @mockFiles.push({name: "fake.pdf"})
+    it "should render with a PDF selected", ->
+        file = {name: "fake.pdf", "type": "application/pdf"}
+        @mockFiles.push(file)
+        @model.set("selectedFile", file)
         @view.render()
         expect(@view.$el).toContain("input[type=file]")
+        expect(@view.$el).not.toContain("p.error")
         expect(@view.$(".action-upload")).not.toBeDisabled()
 
+    it "should render an error with an invalid file type selected", ->
+        file = {name: "fake.png", "type": "image/png"}
+        @mockFiles.push(file)
+        @model.set("selectedFile", file)
+        @view.render()
+        expect(@view.$el).toContain("input[type=file]")
+        expect(@view.$el).toContain("p.error")
+        expect(@view.$(".action-upload")).toBeDisabled()
+
+
     it "adds body class on show()", ->
         @view.show()
         expect(@view.options.shown).toBeTruthy()