library(checkmate)
library(R6)

expect_man_exists = function(man) {
  checkmate::expect_string(man, na.ok = TRUE, fixed = "::")
  if (!is.na(man)) {
    parts = strsplit(man, "::", fixed = TRUE)[[1L]]
    matches = help.search(parts[2L], package = parts[1L], ignore.case = FALSE)
    checkmate::expect_data_frame(matches$matches, min.rows = 1L, info = "man page lookup")
  }
}