run content migration attachment creation through instfs

test plan:
* have instfs enabled
* import a zip file into a course
* the attachments should have instfs_uuids

closes #LS-1285

Change-Id: I42e877e25dfcbd855bfc9e56b59cf969ea7d6ce0
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/244749
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Robin Kuss <rkuss@instructure.com>
Product-Review: James Williams <jamesw@instructure.com>

lib/file_in_context.rb

@@ -49,7 +49,8 @@ class FileInContext
 
       uploaded_data = Rack::Test::UploadedFile.new(filename, Attachment.mimetype(explicit_filename || filename))
 
-      @attachment = Attachment.new(:context => context, :uploaded_data => uploaded_data, :display_name => display_name, :folder => folder)
+      @attachment = Attachment.new(:context => context, :display_name => display_name, :folder => folder)
+      Attachments::Storage.store_for_attachment(@attachment, uploaded_data)
       @attachment.filename = explicit_filename if explicit_filename
       @attachment.set_publish_state_for_usage_rights
       @attachment.save!

spec/models/content_migration_spec.rb

@@ -217,6 +217,17 @@ describe ContentMigration do
       test_zip_import(@course, cm)
     end
 
+    it "should go through instfs if enabled" do
+      cm = setup_zip_import(@course)
+      allow(InstFS).to receive(:enabled?).and_return(true)
+      @uuid = "1234-abcd"
+      allow(InstFS).to receive(:direct_upload).and_return(@uuid)
+
+      test_zip_import(@course, cm)
+      attachment = @course.attachments.last
+      expect(attachment.instfs_uuid).to eq(@uuid)
+    end
+
     it "should import into a user" do
       cm = setup_zip_import(@user)
       test_zip_import(@user, cm)