Test the value of a particular thing and put it in a variable.
Failed tests will result in the specified result variable being cleared.
File tests: directories always have 0 size and their modification time is the time a file was last added or deleted from them. File type is either file or dir.
Contact lookups are based on the phone number of the contact.
Calendar values require the time in seconds since the epoch as data (e.g. use %TIMES, or use the Variable Convert action to convert a date/time into seconds first) and are entered in an array (%var1, %var2 etc), not a plain value, because there may be multiple events at the time specified.