add testthat helper fn for roxy tag

tests/testthat/helper-pkg-skeleton.R

@@ -0,0 +1,116 @@
+make_pkg_path <- function(base_dir = tempdir(), pkg_name = "demo") {
+
+  d <- file.path(base_dir, pkg_name)
+  if (!dir.exists(d)) {
+        dir.create(d, recursive = TRUE)
+    }
+
+    return (d)
+}
+
+get_roxygen_version <- function() {
+
+  ip <- as.data.frame(utils::installed.packages ())
+  if (!"roxygen2" %in% ip$Package) {
+      return(NULL)
+  } # nocov
+
+  return(ip$Version[ip$Package == "roxygen2"])
+}
+
+write_desc <- function(d, pkg_name) {
+
+  desc <- c (
+    paste0 ("Package: ", pkg_name),
+    "Title: What the Package Does (One Line, Title Case)",
+    "Version: 0.0.0.9000",
+    "Authors@R: ",
+    "  person(given = \"First\",",
+    "         family = \"Last\",",
+    "         role = c(\"aut\", \"cre\"),",
+    "         email = \"[email protected]\")",
+    "Description: What the package does (one paragraph).",
+    "Suggests:",
+    "    testthat",
+    "License: GPL-3",
+    "Encoding: UTF-8"
+  )
+
+  rv <- get_roxygen_version()
+  if (!is.null (rv)) {
+
+    desc <- c(
+      desc,
+      paste0 (
+        "Roxygen: list(markdown = TRUE, ",
+        "roclets = c(\"collate\", \"rd\", \"namespace\", \"vcr::examplesVCR_roclet\"))"
+      )
+    )
+  }
+
+  writeLines(desc, con = file.path (d, "DESCRIPTION"))
+}
+
+write_r_fn <- function(d, pkg_name) {
+
+  rfile <- c (
+      "#' test_fn",
+      "#'",
+      "#' A test funtion",
+      "#'",
+      "#' @examplesVCR test_fn",
+      "#' test_fn",
+      "#'",
+      "#' @export",
+      "test_fn <- function() {",
+      "  message(\"This function does nothing\")",
+      "}"
+  )
+  dr <- file.path (d, "R")
+  if (!dir.exists(dr)) {
+      dir.create (dr, recursive = TRUE)
+  }
+  writeLines(rfile, con = file.path(dr, "test.R"))
+
+  rfile <- c(
+      "#' @keywords internal",
+      "\"_PACKAGE\"",
+      "",
+      paste0 (
+        "# The following block is used by ",
+        "usethis to automatically manage"
+      ),
+      "# roxygen namespace tags. Modify with care!",
+      "## usethis namespace: start",
+      "## usethis namespace: end",
+      "NULL"
+  )
+  writeLines(rfile, con = file.path(dr, paste0(pkg_name, "-package.R")))
+}
+
+#' Make skeleton package to test roclet system
+#'
+#' @param base_dir The base directory where the package should be constructed.
+#' @param pkg_name The name of the package. The final location of this package
+#' will be in `file.path(base_dir, pkg_name)`.
+#' @return The path to the directory holding the newly created package
+#' @family helper
+#' @export
+vcr_tests_pkg_skeleton <- function(base_dir = tempdir(), pkg_name = "demo") {
+
+    d <- make_pkg_path(base_dir, pkg_name)
+
+    if (length(list.files(d, recursive = TRUE)) > 0L) {
+        stop (
+            "The path [", d, "] is not empty; ",
+            "can only make a package in an empty directory\n",
+            "  Directory can be cleared with ",
+            "'unlink(<dir>, recursive = TRUE)'"
+        )
+    }
+
+    write_desc(d, pkg_name)
+    write_r_fn(d, pkg_name)
+
+    return(d)
+}