anchor.diff:  ----
   openapi: 3.0.0
   servers:
  -- url: http://definition1
  +- url: http://{var1}.definition1/{var2}
     description: definition server 1
     variables:
       var1:
  
positive.code:             - "1"
              - "2"
              default: "1"
        - url: http://class2
          description: class server 2
          variables:
            var1:
  
negative.code:         default:
            description: default response
        servers:
        - url: http://{var1}.class1/{var2}
          description: class server 1
          variables:
            var1:
  