Move requires_package to r/utils.R and add tests

R/ggplot2.R

   family
 }
 
-requires_package <- function(pkg = "ggplot2", fn = "", required = TRUE) {
-  raise <- if (required) stop else warning
-  if (!requireNamespace(pkg, quietly = TRUE)) {
-    msg <- paste0(
-      "`",
-      pkg,
-      "` is ",
-      if (required) "required " else "suggested ",
-      if (fn != "") paste0("by ", fn, "() ")[1],
-      "but is not installed."
-    )
-    raise(msg, call. = FALSE)
-    invisible(FALSE)
-  }
-  invisible(TRUE)
-}
-
 requires_xaringanthemer_env <- function(
   css_file = NULL,
   try_css = TRUE,

R/utils.R

   lum[1, 1] > 0.179
 }
 
+requires_package <- function(pkg = "ggplot2", fn = "", required = TRUE) {
+  raise <- if (required) stop else warning
+  if (!requireNamespace(pkg, quietly = TRUE)) {
+    msg <- paste0(
+      "`",
+      pkg,
+      "` is ",
+      if (required) "required " else "suggested ",
+      if (fn != "") paste0("by ", fn, "() ")[1],
+      "but is not installed."
+    )
+    raise(msg, call. = FALSE)
+    return(invisible(FALSE))
+  }
+  invisible(TRUE)
+}
+
 #' @keywords internal
 call_style_xaringan <- function() {
   paste0(

tests/testthat/test-utils.R

     "google-font-print.txt"
   )
 })
+
+test_that("requires_package()", {
+  expect_true(requires_package("purrr"))
+  expect_error(requires_package("notapackage", "myFunction"), "myFunction")
+  expect_warning(requires_package("notapackage", required = FALSE))
+  expect_false(requires_package("notapackage", required = FALSE))
+})