[O] org-export-region-as-latex skips header

[Christopher Schmidt]

Org-mode version 7.9.2 (release_7.9.2-52-g921998)

C-x b test RET
insert "* dub"
M-: (org-export-region-as-latex (point-min) (point-max) nil 'string) RET

org-export-region-as-latex returns

    "\\section{dub}\n\\label{sec-1}\n\n\\end{document}\n"

This does not look right to me.  Where is the header?

        Christopher