write tests

[eeholmes]

see how rredlist did this

use roxytest

Suggests: testthat, roxytest
Roxygen: list(roclets = c("namespace", "rd", "roxytest::testthat_roclet"))

Suggests: testthat, tinytest
BugReports: https://github.com/mikldk/roxytestdemo/issues
Encoding: UTF-8
Roxygen: list(roclets = c("namespace", "rd", "roxytest::testthat_roclet",
                                             "roxytest::tinytest_roclet", 
                                             "roxytest::param_roclet", 
                                             "roxytest::return_roclet", 
                                             "roxytest::examples_roclet"))