#describe backup tests aren't actually testing anything

[Gergely Brautigam]

The test in backup_tests.rb, namly these guys: describe '#backup' do, aren't actually testing anything.

They only test mock calls because of allow expect. I can delete every function like, tar, zip, upload and the tests are still green after subject.upload.

I'm order to actually test s3_client, AWS files need to be mocked because of fakefs. For a working example have a look at client_test.rb after the PR has been merged.

Example spoofing AWS

 before(:all) do
    # Using doubles without context is unsupported. with_temporary_scope to the rescue.
    RSpec::Mocks.with_temporary_scope do
      allow(Aws::S3::Client).to receive(:new).and_return(instance_double(Aws::S3::Client))
    end
  end
  ...
  Aws.config[:s3] = {
    stub_responses: {
      list_objects: { contents: contents }
    }
  }