# Yggdrasil Tutorial part three

This tutorial assumes you have understood part two.

For comments or questions please contact Petur Olsen at `petur@cs.aau.dk` or Marius Mikucionis `marius@cs.aau.dk`.

## Using the Query File

Open the updown.xml file in Uppaal.

This tutorial uses the same model as part two.

Sometimes it is desirable to generate test cases for specific purposes. This can be done in Yggdrasil by creating a verification query for the purpose, and using it to generate a test case.

In the `Verifier` tab you can enter queries. Yggdrasil searches for all reachability queries (that is queries which start with '`E<>`').

The query enterer should be `E<> System.Max`, which asks the verifier to find a trace where the `System` process is in the location `Max`.

To generate test cases go to the `Yggdrasil` tab and activate the `Query file` option, and hit `Generate`.

This should generate a trace from the query file. You can double click the trace and go to the `Simulator` tab and verify that this trace does indeed lead to the `Max` location.

This is the end of the tutorial series.

Please send any questions or comments to Petur Olsen at `petur@cs.aau.dk`.