write test

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

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

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

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