Integrate trigger behavior with unit tests

Make some changes to (or add another) trigger behavior of the Response() function in requests.
There should be a possibility to add the unit tests to the request history or access the request history of unit tests.
Example usage:
Unit tests add a category. For this category 2 subcategories need to be created by specifying the first category's id as parent id.
When you now use "Always" trigger behavior you have 4 categories, not 3. One parent and sub-category and another.
When you use the history the requests sent by the unit-tests are not considered - therefore it is not possible (or at least I don't know how) to create unit tests for my scenario.