default-can-be-prefix-*.cpp verifies the effect of Interest::setDefaultCanBePrefix. They are written as integration tests because ndn-cxx unit tests are prohibited from calling Interest::setDefaultCanBePrefix.
Manual verification steps:
default-can-be-prefix-unset program should print a "CanBePrefix unset" warning to stderr.default-can-be-prefix-0 and default-can-be-prefix-1 test cases should not print that warning.