Fix instructor notes 505

DESCRIPTION

@@ -23,6 +23,10 @@ Authors@R: c(
            family = "Michonneau",
            role = c("ctb"),
            email = "[email protected]"),
+    person(given = "Kelly",
+           family = "Barnes",
+           role = c("ctb"),
+           email = "[email protected]"),
     person())
 Description: We provide tools to build a Carpentries-themed lesson repository
   into an accessible standalone static website. These include local tools and

NEWS.md

@@ -16,6 +16,8 @@
   version comparisons always use characters and not numbers (which is
   ergonomically weird, but whatever) (reported: @zkamvar #487; fixed: @zkamvar
   #487)
+* Blank instructor notes pages no longer fail to build 
+  (reported: @apirogov, #505; fixed: @klbarnes20, #509)
 * Tests for {renv} post 1.0.0 fixed so that they no longer run forever
   interactively (reported: @zkamvar #500; fixed: @zkamvar, #501)
 

R/build_instructor_notes.R

@@ -17,6 +17,8 @@ build_instructor_notes <- function(pkg, pages = NULL, built = NULL, quiet) {
     if (html != '') {
       html  <- xml2::read_html(html)
       fix_nodes(html)
+    } else {
+      html <- xml2::read_html("<p></p>")
     }
 
     this_dat <- list(

tests/testthat/test-build_lesson.R

@@ -165,6 +165,36 @@ test_that("instructor-notes page can be rebuilt", {
 
 })
 
+test_that("empty instructor notes build", {
+  skip_if_not(rmarkdown::pandoc_available("2.11"))
+  # 0. Test that the placeholder text exists in the rendered instructor notes
+  build_instructor_notes(pkg, pages = htmls, quiet = TRUE)
+  expect_true(any(grepl(
+    "This is a placeholder file.",
+    readLines(fs::path(sitepath, "instructor-notes.html"))
+  )))
+  # 1. make a copy of the instructor-notes.md to a local tempfile (use tmp <-
+  # withr::local_tempfile() and fs::file_copy()
+  tmp <- withr::local_tempfile()
+  fs::file_copy(fs::path(res, "instructors/instructor-notes.md"), tmp)
+  # 2. use withr::defer() to do the opposite, copying over the saved file back
+  # when the test finishes)
+  withr::defer({
+    fs::file_copy(tmp, fs::path(res, "instructors/instructor-notes.md"), overwrite = TRUE)
+  }, priority = "first")
+  # 3. replace the instructor-notes.md with "---\ntitle: test\n---\n" using the
+  # writeLines() function
+  writeLines("---\ntitle: test\n---\n", fs::path(res, "instructors/instructor-notes.md"))
+  # 4. test that build_instructor_notes() builds the notes and doesn't throw an
+  # error.
+  expect_no_error(build_instructor_notes(pkg, pages = htmls, quiet = TRUE))
+  # 5. test for the absence of placeholder text
+  expect_false(any(grepl(
+    "This is a placeholder file.",
+    readLines(fs::path(sitepath, "instructor-notes.html"))
+  )))
+})
+
 test_that("sitemap exists", {
   skip_if_not(rmarkdown::pandoc_available("2.11"))
   sitemap <- fs::path(sitepath, "sitemap.xml")