adjust filename for ePub to be more user friendly

closes CNVS-25065

test plan:
- export an ePub that has unsupported media types
- the ePub filename should reflect courseName-Timestamp
- the zip filename should reflect the local timestamp
- timestamp pattern should be 2015-Nov-16_18-22-40
- a course name over 200 chars in length should be truncated to the 200th
  char

Change-Id: I39829d1df050b30544381c7ef20deba5c8c414d1
Reviewed-on: https://gerrit.instructure.com/67205
Reviewed-by: John Corrigan <jcorrigan@instructure.com>
Tested-by: Jenkins
QA-Review: Deepeeca Soundarrajan <dsoundarrajan@instructure.com>
Product-Review: Cosme Salazar <cosme@instructure.com>

lib/cc/exporter/epub/book.rb

@@ -54,7 +54,9 @@ module CC::Exporter::Epub
     end
 
     def filename
-      "#{pub_id}.#{title}.epub"
+      name = CanvasTextHelper.truncate_text(title, {:max_length => 200, :ellipsis => ''})
+      timestamp = Time.zone.now.strftime('%Y-%b-%d_%H-%M-%S')
+      "#{name}-#{timestamp}.epub"
     end
   end
 end

lib/cc/exporter/epub/files_directory.rb

@@ -36,7 +36,7 @@ module CC::Exporter::Epub
     end
 
     def filename
-      @_filename ||= "#{SecureRandom.uuid}.zip"
+      @_filename ||= "#{Time.zone.now.strftime('%Y-%b-%d_%H-%M-%S')}.zip"
     end
 
     def zip_file

lib/cc/exporter/epub/templates/assignments_template.html.erb

@@ -6,7 +6,7 @@
   <p><%= item[:lock_at] ? I18n.t("Lock at: %{time}",{time: friendly_date(item[:lock_at])}) : nil %></p>
   <p><%= item[:grading_type] ? I18n.t("Grading Type: %{type}",{type: item[:grading_type]}) : nil %></p>
   <p><%= item[:points_possible] ? I18n.t("Points: %{points}",{points: item[:points_possible]}) : nil %></p>
-  <% if item[:submission_types].any? %>
+  <% if item[:submission_types].try(:any?) %>
     <p><%= I18n.t("Submitting: %{types}", { types: item[:submission_types].join(', ') }) %></p>
   <% end %>
 </div>

spec/lib/cc/exporter/epub/exportable_spec.rb

@@ -19,12 +19,17 @@ describe "Exportable" do
   end
 
   context "#convert_to_epub" do
+
+    before do
+      @epub_export = ExportableTest.new.convert_to_epub
+    end
+
     let(:epub_path) do
-      ExportableTest.new.convert_to_epub.first
+      @epub_export.first
     end
 
     let(:zip_path) do
-      ExportableTest.new.convert_to_epub.last
+      @epub_export.last
     end
 
     let(:epub) do