export an empty zip

closes OFFW-37

test plan:
- it should export an empty zip file

(the other parts of this aren't wired up yet, so good luck getting to this)

Change-Id: Ied37e879a274c423c3393659e8557f69c7a0cc82
Reviewed-on: https://gerrit.instructure.com/96555
Tested-by: Jenkins
Reviewed-by: Jon Willesen <jonw+gerrit@instructure.com>
QA-Review: Nathan Rogowski <nathan@instructure.com>
Product-Review: Cameron Sutter <csutter@instructure.com>

lib/cc/exporter/web_zip/exportable.rb

@@ -0,0 +1,15 @@
+module CC::Exporter::WebZip
+  module Exportable
+    def content_cartridge
+      self.attachment
+    end
+
+    def convert_to_offline_web_zip
+      exporter = CC::Exporter::WebZip::Exporter.new(content_cartridge.open, false)
+      zip = CC::Exporter::WebZip::ZipPackage.new(exporter)
+      result = zip.create
+      exporter.cleanup_files
+      result
+    end
+  end
+end

lib/cc/exporter/web_zip/exporter.rb

@@ -0,0 +1,9 @@
+module CC::Exporter::WebZip
+  class Exporter < CC::Exporter::Epub::Exporter
+
+    # override epub exporter templates
+    def templates
+
+    end
+  end
+end

lib/cc/exporter/web_zip/zip_package.rb

@@ -0,0 +1,5 @@
+module CC::Exporter::WebZip
+  class ZipPackage < CC::Exporter::Epub::FilesDirectory
+
+  end
+end

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

@@ -0,0 +1,48 @@
+# coding: utf-8
+require File.expand_path(File.dirname(__FILE__) + '/../../cc_spec_helper')
+
+describe "Exportable" do
+  class ExportableTest
+    include CC::Exporter::WebZip::Exportable
+
+    def attachment
+      @_attachment ||= Attachment.create({
+        context: Course.create,
+        filename: 'exportable-test-file',
+        uploaded_data: File.open(cartridge_path)
+      })
+    end
+
+    def cartridge_path
+      File.join(File.dirname(__FILE__), "/../../../../fixtures/migration/unicode-filename-test-export.imscc")
+    end
+  end
+
+  context "#convert_to_epub" do
+
+    before do
+      @epub_export = ExportableTest.new.convert_to_offline_web_zip
+    end
+
+    let(:zip_path) do
+      @epub_export
+    end
+
+    let(:zip) do
+      File.open(zip_path)
+    end
+
+    it "should create a zip file" do
+      expect(zip).not_to be_nil
+    end
+
+    it "creates a zip file whose name includes the cartridge's name" do
+      expect(zip_path).to include('unicode-filename-test')
+    end
+
+    after do
+      File.delete(zip_path) if File.exist?(zip_path)
+    end
+  end
+
+end

spec/lib/cc/exporter/web_zip/exporter_spec.rb

@@ -0,0 +1,29 @@
+# coding: utf-8
+require File.expand_path(File.dirname(__FILE__) + '/../../cc_spec_helper')
+
+describe "Exporter" do
+  include CC::Exporter::WebZip
+
+  before(:once) do
+    def cartridge_path
+      File.join(File.dirname(__FILE__), "/../../../../fixtures/exporter/cc-with-modules-export.imscc")
+    end
+
+    @attachment = Attachment.create({
+      context: course,
+      filename: 'exportable-test-file',
+      uploaded_data: File.open(cartridge_path)
+    })
+
+  end
+
+  context "create web zip package default settings" do
+    let(:exporter) do
+      CC::Exporter::WebZip::Exporter.new(@attachment.open)
+    end
+
+    it "should sort content by module" do
+      expect(exporter.base_template).to eq "../templates/module_sorting_template.html.erb"
+    end
+  end
+end