Supplementary hints

Condition values can be understood as (input) equivalence classes

and thus also invalid equivalence classes are meant
that is why LF‑ET provides statistics as to equivalence class coverage
see also: options for equivalence class creation

Irrelevant in a condition ("-") can be handled differently

an incidental occurrence is used which is defined as a valid equivalence class in order to obtain a test step
no occurrence is selected and no test step is generated
see also: creating test instructions for irrelevant conditions and options for equivalence class creation

No action can be the expected behaviour of the system

and that is why in the case of actions also test instructions for the "-" value can be created
see also: Test instructions for not used actions

Warnings and error messages are also the expected behaviour of the system

and should be specified precisely in the requirements
and should be assumed as actions in the decision table
see also: Test instructions with categories