The practice of component interface testing can be used to check the handling of data passed between various units, or subsystem components, beyond full integration testing between those units. The data being passed can be considered as "message packets" and the range or data types can be checked, for data generated from one unit, and tested for validity before being passed into another unit. One option for interface testing is to keep a separate log file of data items being passed, often with a timestamp logged to allow analysis of thousands of cases of data passed between units for days or weeks. Tests can include checking the handling of some extreme data values while other interface variables are passed as normal values. Unusual data values in an interface can help explain unexpected performance in the next unit. Component interface testing is a variation of black-box testing, with the focus on the data values beyond just the related actions of a subsystem component.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is a variation of black-boxing testing?
Ah, so.. unanswerable

The U.S. Army black beret (having been permanently replaced with the patrol cap) is no longer worn with the new ACU for garrison duty. After years of complaints that it wasn't suited well for most work conditions, Army Chief of Staff General Martin Dempsey eliminated it for wear with the ACU in June 2011. Soldiers still wear berets who are currently in a unit in jump status, whether the wearer is parachute-qualified, or not (maroon beret), Members of the 75th Ranger Regiment and the Airborne and Ranger Training Brigade (tan beret), and Special Forces (rifle green beret) and may wear it with the Army Service Uniform for non-ceremonial functions. Unit commanders may still direct the wear of patrol caps in these units in training environments or motor pools.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What color beret does the member of the 76th Ranger Regiment wear?
Ah, so.. unanswerable

On April 15, 2013, two Chechen Islamist brothers exploded two bombs near the finish line of the Boston Marathon, killing three people and injuring roughly 264.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): How many fatalities were there at the marathon?
Ah, so..
three