add specs for #client

spec/unit/request/client_spec.rb

@@ -0,0 +1,8 @@
+require 'spec_helper'
+
+describe Zero::Request, '#client' do
+  subject { Zero::Request.new(env) }
+  let(:env) { EnvGenerator.get('/foo') }
+
+  its(:client) { should be_an_instance_of(Zero::Request::Client) }
+end