prevent test from running on appveyor

Author: bvogelzang

Diff for: test/client_test.rb

@@ -130,7 +130,7 @@ class ClientTest < TinyTds::TestCase
     end
 
     it 'raises TinyTds exception with sql batch timeout due to network failure' do
-      skip if ENV['CI'] && sqlserver_azure?
+      skip if ENV['CI'] && ENV['APPVEYOR_BUILD_FOLDER'] # only CI using docker
       begin
         client = new_connection timeout: 2
         assert_client_works(client)