anchor.diff:  
       let buildCfg' = buildCfg parse createCfg astToDot tokToRealName
   
  -    let runTest' (cfg : ControlFlow<_>) (expected : string list) = 
  -        runTest tokToRealName cfg expected
  -
  -    [<Test>]
  -    member test.``Elementary``() = 
  +    [<Test>]
  +    member test.``X = Z; Y = X;``() = 
           let qGraph = createParserInput' "X = Z; Y = X.dot"
   
           let expected = [z]
  -        let prefix = "`cfg undefined variables elementary"
  -        //act
  -        let cfg = buildCfg' qGraph prefix
  -        //assert
  -        runTest' cfg expected
  +        let prefix = "`cfg undefined variables X = Z; Y = X"
  +        
  +        //act
  +        let cfg = buildCfg' qGraph prefix
  +        let errorList = 
  +            cfg.FindUndefinedVariables()
  +            |> List.map tokToRealName
  +        
  +        //assert
  +        assertResult errorList expected
   
       [<Test>]
       member test.``X = X``() = 
  
positive.code:         
          let expected = [y]
          let prefix = "`cfg undefined variables ambiguous2"
          //act
          let cfg = buildCfg' qGraph prefix
          //assert
          runTest' cfg expected
  
      [<Test>]
      member this.``Cycle inside expression``() = 
  
negative.code:         let prefix = "`scope2"
  
          let expected = []
          
          //act
          let cfg = buildCfg' qGraph prefix
          let errorList = 
              cfg.FindUndefinedVariables()
              |> List.map tokToRealName
          
          //assert
          assertResult errorList expected
  
      [<Test>]
      member this.``Scope3``() = 
  