add test C++ function support on FFI
add test C++ function support on FFI

felipensp/clever,felipensp/clever,clever-lang/clever,clever-lang/clever,felipensp/clever,clever-lang/clever,felipensp/clever,felipensp/clever,felipensp/clever,felipensp/clever,clever-lang/clever,clever-lang/clever,clever-lang/clever,clever-lang/clever