anchor.diff:  To get a feeling how Sakuli reacts on errors we will modify the testcase definition `sakuli_demo.js` to a not present link validation and force an error through this:
   
   .link:part_02/sakuli-tests/example_xfce/case1/sakuli_demo.js[`part_02/sakuli-tests/example_xfce/case1/sakuli_demo.js`]
  -[soruce,js]
  +[source,js]
   ----
   ...
   try {
  
positive.code: image:.pics/ui_content_testing.png[Native UI component: Calculator  gedit]
  
  The implementation of the test case is very simple, you can just mix web and native testing methods. Take a look at the file: link:part_01/example_xfce/case1/sakuli_demo.js[`part_01/example_xfce/case1/sakuli_demo.js`].
  [source, js]
  ----
  _dynamicInclude($includeFolder);
  var testCase = new TestCase(40, 60);
  
negative.code: 
  To define a warning time for the test case, the http://consol.github.io/sakuli/latest/index.html#TestCase[`TestCase`] object have been used:
  
  [source,js]
  ----
  var testCase = new TestCase(40, 60);
  ----
  
  The second threshold of `60` seconds, define the critical time. It's also possible define a global waring and critical times for the whole test suite in the file link:part_01/example_xfce/testsuite.properties[`/part_01/example_xfce/testsuite.properties`], if you have more testcases. After all you get this datamodel:
  
  [source,bash]
  ----
  TestSuite: example_xfce, warning time: 50, critical time: 70
  |---- TestCase: case1, warning time: 40, critical time: 60
  