You can test individual Declare Expression rules as a unit before the rules are integrated into the rest of the application that is under development.
Unit testing is available only for Declare Expression rules for which all properties referenced in the expression belong to a single Applies To class or to one class plus superclasses of that class. For example, you cannot use this facility to test a computation that involves both a Data-Account property and an Assign-Workbasket property.
If the expressions involve aggregate properties, use this facility only with Page Group or Page List properties with a small number of elements.
To avoid infinite loops caused by recursion, this facility uses an internal limit of 999 computations, counting both iterations over List and Group properties and expression evaluations. If this limit is reached during a test execution, the evaluation ends with an error message.
Your expression can involve special properties (standard properties with names starting with px or your properties marked as special), Value List, or Value Group properties.
You cannot use manual inputs to change the value of a special property. Instead, you can make changes to special properties by using a data transform that you can run from Actions > Run.