Migrate tests

R/stan_cmdstan_exists.R

@@ -1,14 +1,20 @@
-#' @title Check if `instantiate` can find CmdStan.
+#' @title Check if `instantiate` can find CmdStanR and CmdStan.
 #' @export
 #' @family cmdstan
-#' @description Check if `instantiate` can find CmdStan.
+#' @description Check if `instantiate` can find CmdStanR and CmdStan.
 #' @inheritParams stan_cmdstan_path
-#' @return `TRUE` if `instantiate` can find CmdStan, `FALSE` otherwise.
+#' @return `TRUE` if `instantiate` can find the CmdStanR R package and the
+#'   CmdStan command line tool. Returns `FALSE` otherwise.
 #' @examples
 #' stan_cmdstan_exists()
 stan_cmdstan_exists <- function(
   cmdstan_install = Sys.getenv("CMDSTAN_INSTALL", unset = "")
 ) {
+  # nocov start
+  if (!rlang::is_installed("cmdstanr")) {
+    return(FALSE) # Not possible to cover in regular unit tests.
+  }
+  # nocov end
   path <- stan_cmdstan_path(cmdstan_install = cmdstan_install)
   cmdstan_valid(path)
 }

R/stan_cmdstan_path.R

@@ -29,6 +29,11 @@
 stan_cmdstan_path <- function(
   cmdstan_install = Sys.getenv("CMDSTAN_INSTALL", unset = "")
 ) {
+  # nocov start
+  if (!rlang::is_installed("cmdstanr")) {
+    return("") # Not possible to cover in regular unit tests.
+  }
+  # nocov end
   install <- if_any(
     identical(cmdstan_install, ""),
     .Call(c_cmdstan_path_install, PACKAGE = "instantiate"),
@@ -44,5 +49,5 @@ stan_cmdstan_path <- function(
     cmdstan_valid(path),
     path,
     cmdstanr("cmdstan_default_path")(dir = path)
-  ) %|||% NULL
+  ) %|||% ""
 }

R/stan_cmdstan_version.R

@@ -7,7 +7,8 @@
 #'   package uses. If CmdStan is not found, then the return value depends
 #'   on the `error_on_NA` argument.
 #' @inheritParams stan_cmdstan_path
-#' @inheritParams cmdstanr::cmdstan_version
+#' @param error_on_NA Logical of length 1, whether an error should be thrown
+#'   if CmdStan is not found.
 #' @examples
 #' if (stan_cmdstan_exists()) {
 #'   message(stan_cmdstan_version())