Do all exported functions have a corresponding testthat unit test file?

check_exported_fn_for_unit_tests.R

library(magrittr)
exported_functions <- 
  readr::read_lines("NAMESPACE") %>% 
  stringr::str_extract("(?<=export\\().+(?=\\))") %>% 
  .[!is.na(.)]

unit_tests <- 
  list.files("tests/testthat/") %>% 
  stringr::str_extract("(?<=test-).+(?=\\.R)") %>% 
  .[!is.na(.)]

# Do all exported functions have a unit test file named after them?
all(exported_functions %in% unit_tests)

# Which ones do not? 
exported_functions[!exported_functions %in% unit_tests]