refactor

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>
refactor expandFuncCall()

- and add test

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>
buggy

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>
fixed... ???

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>