From 4503f76006ed74cea6e67318283f284589a77573 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Tue, 22 Jun 2021 12:59:07 -0700
Subject: [PATCH 01/23] Move exercise error checking code into
 `evaluate_exercise()` from `render_exercise()`

---
 R/exercise.R                   | 49 ++++++++++++++++++++++------------
 tests/testthat/test-exercise.R | 38 ++++++++++++++++----------
 2 files changed, 56 insertions(+), 31 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 06c360935..10130bc8b 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -318,9 +318,31 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
   }
 
   # Resolve knitr options for the exercise and setup chunks
+  # evaluate() ####
   rmd_results <- withr::with_dir(
     exercise_dir,
-    render_exercise(exercise, envir)
+    tryCatch(
+      render_exercise(exercise, envir),
+      error = function(e) {
+        if (length(exercise$error_check)) {
+          # Run the condition through an error checker
+          # (the exercise could be to throw an error!)
+          checker_feedback <- try_checker(
+            exercise, "exercise.checker",
+            check_code = exercise$error_check,
+            envir_result = e$envir_result,
+            evaluate_result = e$evaluate_result,
+            envir_prep = e$envir_prep,
+            last_value = e$e,
+            engine = exercise$engine
+          )
+          if (is_exercise_result(checker_feedback)) {
+            return(checker_feedback)
+          }
+        }
+        exercise_result_error(e$msg)
+      }
+    )
   )
 
   if (is_exercise_result(rmd_results)) {
@@ -533,6 +555,7 @@ render_exercise <- function(exercise, envir) {
     envir_result <- duplicate_env(envir_prep)
 
     # Now render user code for final result
+    # render() ####
     rmarkdown::render(
       input = rmd_file_user,
       output_format = output_format_exercise(user = TRUE),
@@ -548,22 +571,14 @@ render_exercise <- function(exercise, envir) {
     if (grepl(pattern, msg, fixed = TRUE)) {
       return(exercise_result_timeout())
     }
-    if (length(exercise$error_check)) {
-      # Run the condition through an error checker (the exercise could be to throw an error!)
-      checker_feedback <- try_checker(
-        exercise, "exercise.checker",
-        check_code = exercise$error_check,
-        envir_result = envir_result,
-        evaluate_result = evaluate_result,
-        envir_prep = envir_prep,
-        last_value = e,
-        engine = exercise$engine
-      )
-      if (is_exercise_result(checker_feedback)) {
-        return(checker_feedback)
-      }
-    }
-    exercise_result_error(msg)
+    rlang::abort(
+      class = "learnr_exercise_result",
+      envir_result = envir_result,
+      evaluate_result = evaluate_result,
+      envir_prep = envir_prep,
+      last_value = e,
+      error_message = msg
+    )
   })
 
   if (is_exercise_result(output_file)) {
diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index 7fd6612dc..f37c729ac 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -140,11 +140,9 @@ test_that("render_exercise() returns identical envir_prep and envir_result if an
     error_check = "unevaluated, triggers error_check in render_exercise()"
   )
 
-  exercise_result <- withr::with_tempdir(render_exercise(exercise, new.env()))
-
-  # the error during render causes a checker evaluation, so we can recover
-  # the environments from the checker_args returned by the debug checker
-  exercise_result <- exercise_result$feedback$checker_args
+  exercise_result <- withr::with_tempdir(
+    tryCatch(render_exercise(exercise, new.env()), error = identity)
+  )
 
   expect_s3_class(exercise_result$last_value, "simpleError")
   expect_equal(conditionMessage(exercise_result$last_value), "boom")
@@ -162,11 +160,9 @@ test_that("render_exercise() returns envir_result up to error", {
     error_check = "unevaluated, triggers error_check in render_exercise()"
   )
 
-  exercise_result <- withr::with_tempdir(render_exercise(exercise, new.env()))
-
-  # the error during render causes a checker evaluation, so we can recover
-  # the environments from the checker_args returned by the debug checker
-  exercise_result <- exercise_result$feedback$checker_args
+  exercise_result <- withr::with_tempdir(
+    tryCatch(render_exercise(exercise, new.env()), error = identity)
+  )
 
   expect_s3_class(exercise_result$last_value, "simpleError")
   expect_equal(conditionMessage(exercise_result$last_value), "boom")
@@ -184,13 +180,17 @@ test_that("render_exercise() with errors and no checker returns exercise result
     setup_label = "setup-1"
   )
 
-  exercise_result <- withr::with_tempdir(render_exercise(exercise, new.env()))
+  exercise_result <- withr::with_tempdir(
+    tryCatch(render_exercise(exercise, new.env()), error = identity)
+  )
   expect_s3_class(exercise_result, "learnr_exercise_result")
   expect_identical(exercise_result$error_message, "setup")
   expect_null(exercise_result$feedback)
 
   exercise <- mock_exercise(user_code = "stop('user')")
-  exercise_result <- withr::with_tempdir(render_exercise(exercise, new.env()))
+  exercise_result <- withr::with_tempdir(
+    tryCatch(render_exercise(exercise, new.env()), error = identity)
+  )
   expect_s3_class(exercise_result, "learnr_exercise_result")
   expect_identical(exercise_result$error_message, "user")
   expect_null(exercise_result$feedback)
@@ -228,8 +228,18 @@ test_that("render_exercise() cleans up exercise_prep files even when setup fails
 
   files <- expect_message(
     withr::with_tempdir({
-      before <-  dir()
-      res <- render_exercise(exercise, new.env())
+      before <- dir()
+      e <- tryCatch(render_exercise(exercise, new.env()), error = identity)
+      res <- try_checker(
+        exercise, "exercise.checker",
+        check_code = exercise$error_check,
+        envir_result = e$envir_result,
+        evaluate_result = e$evaluate_result,
+        envir_prep = e$envir_prep,
+        last_value = e$e,
+        engine = exercise$engine
+      )
+
       list(
         before = before,
         before_error = get("dir_setup", res$feedback$checker_args$envir_prep),

From 259a0821b78992574879dc29e8cdedd54cf651d3 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Tue, 22 Jun 2021 12:59:57 -0700
Subject: [PATCH 02/23] Remove breadcrumbs

---
 R/exercise.R | 2 --
 1 file changed, 2 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 10130bc8b..17da23b40 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -318,7 +318,6 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
   }
 
   # Resolve knitr options for the exercise and setup chunks
-  # evaluate() ####
   rmd_results <- withr::with_dir(
     exercise_dir,
     tryCatch(
@@ -555,7 +554,6 @@ render_exercise <- function(exercise, envir) {
     envir_result <- duplicate_env(envir_prep)
 
     # Now render user code for final result
-    # render() ####
     rmarkdown::render(
       input = rmd_file_user,
       output_format = output_format_exercise(user = TRUE),

From ca144c9f27984ec76803069533c5e992e7482e35 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Wed, 23 Jun 2021 20:40:42 -0700
Subject: [PATCH 03/23] Use more specific error class for render errors

---
 R/exercise.R                   | 2 +-
 tests/testthat/test-exercise.R | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 17da23b40..0c8abbc36 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -570,7 +570,7 @@ render_exercise <- function(exercise, envir) {
       return(exercise_result_timeout())
     }
     rlang::abort(
-      class = "learnr_exercise_result",
+      class = "learnr_render_exercise_error",
       envir_result = envir_result,
       evaluate_result = evaluate_result,
       envir_prep = envir_prep,
diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index f37c729ac..7c0f816bb 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -183,7 +183,7 @@ test_that("render_exercise() with errors and no checker returns exercise result
   exercise_result <- withr::with_tempdir(
     tryCatch(render_exercise(exercise, new.env()), error = identity)
   )
-  expect_s3_class(exercise_result, "learnr_exercise_result")
+  expect_s3_class(exercise_result, "learnr_render_exercise_error")
   expect_identical(exercise_result$error_message, "setup")
   expect_null(exercise_result$feedback)
 
@@ -191,7 +191,7 @@ test_that("render_exercise() with errors and no checker returns exercise result
   exercise_result <- withr::with_tempdir(
     tryCatch(render_exercise(exercise, new.env()), error = identity)
   )
-  expect_s3_class(exercise_result, "learnr_exercise_result")
+  expect_s3_class(exercise_result, "learnr_render_exercise_error")
   expect_identical(exercise_result$error_message, "user")
   expect_null(exercise_result$feedback)
 })

From c3c38ae44185a7fdf780b34c738fedf7bf941798 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Wed, 23 Jun 2021 20:49:48 -0700
Subject: [PATCH 04/23] Simplify test

---
 tests/testthat/test-exercise.R | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index 7c0f816bb..d315fca14 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -229,22 +229,12 @@ test_that("render_exercise() cleans up exercise_prep files even when setup fails
   files <- expect_message(
     withr::with_tempdir({
       before <- dir()
-      e <- tryCatch(render_exercise(exercise, new.env()), error = identity)
-      res <- try_checker(
-        exercise, "exercise.checker",
-        check_code = exercise$error_check,
-        envir_result = e$envir_result,
-        evaluate_result = e$evaluate_result,
-        envir_prep = e$envir_prep,
-        last_value = e$e,
-        engine = exercise$engine
-      )
+      e      <- rlang::catch_cnd(render_exercise(exercise, new.env()))
 
       list(
         before = before,
-        before_error = get("dir_setup", res$feedback$checker_args$envir_prep),
-        during = res$feedback$checker_result,
-        after = dir()
+        during = get("dir_setup", e$envir_prep),
+        after  = dir()
       )
     }),
     "exercise_prep.Rmd"
@@ -253,9 +243,7 @@ test_that("render_exercise() cleans up exercise_prep files even when setup fails
   # start with nothing
   expect_identical(files$before, character(0))
   # prep file is present while evaluating prep
-  expect_identical(files$before_error, "exercise_prep.Rmd")
-  # prep files are cleaned up after error
-  expect_identical(files$during, character(0))
+  expect_identical(files$during, "exercise_prep.Rmd")
   # nothing in directory after render_exercise() because user code didn't evaluate
   expect_identical(files$after, character(0))
 })

From aa6abd7b3878a9d89a9e3176c25b2bcb58484acb Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Wed, 23 Jun 2021 20:50:41 -0700
Subject: [PATCH 05/23] Use `rlang::catch_cnd()` instead of `tryCatch()`

---
 tests/testthat/test-exercise.R | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index d315fca14..78729396a 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -141,7 +141,9 @@ test_that("render_exercise() returns identical envir_prep and envir_result if an
   )
 
   exercise_result <- withr::with_tempdir(
-    tryCatch(render_exercise(exercise, new.env()), error = identity)
+    rlang::catch_cnd(
+      render_exercise(exercise, new.env()), "learnr_render_exercise_error"
+    )
   )
 
   expect_s3_class(exercise_result$last_value, "simpleError")
@@ -161,7 +163,9 @@ test_that("render_exercise() returns envir_result up to error", {
   )
 
   exercise_result <- withr::with_tempdir(
-    tryCatch(render_exercise(exercise, new.env()), error = identity)
+    rlang::catch_cnd(
+      render_exercise(exercise, new.env()), "learnr_render_exercise_error"
+    )
   )
 
   expect_s3_class(exercise_result$last_value, "simpleError")
@@ -181,7 +185,9 @@ test_that("render_exercise() with errors and no checker returns exercise result
   )
 
   exercise_result <- withr::with_tempdir(
-    tryCatch(render_exercise(exercise, new.env()), error = identity)
+    rlang::catch_cnd(
+      render_exercise(exercise, new.env()), "learnr_render_exercise_error"
+    )
   )
   expect_s3_class(exercise_result, "learnr_render_exercise_error")
   expect_identical(exercise_result$error_message, "setup")
@@ -189,7 +195,9 @@ test_that("render_exercise() with errors and no checker returns exercise result
 
   exercise <- mock_exercise(user_code = "stop('user')")
   exercise_result <- withr::with_tempdir(
-    tryCatch(render_exercise(exercise, new.env()), error = identity)
+    rlang::catch_cnd(
+      render_exercise(exercise, new.env()), "learnr_render_exercise_error"
+    )
   )
   expect_s3_class(exercise_result, "learnr_render_exercise_error")
   expect_identical(exercise_result$error_message, "user")
@@ -229,7 +237,9 @@ test_that("render_exercise() cleans up exercise_prep files even when setup fails
   files <- expect_message(
     withr::with_tempdir({
       before <- dir()
-      e      <- rlang::catch_cnd(render_exercise(exercise, new.env()))
+      e      <- rlang::catch_cnd(
+        render_exercise(exercise, new.env()), "learnr_render_exercise_error"
+      )
 
       list(
         before = before,

From 0cb3dfda34d025f7b09cf0db18c6d11a95be9efc Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Wed, 23 Jun 2021 21:03:17 -0700
Subject: [PATCH 06/23] Run code checks before creating temp dir

---
 R/exercise.R | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 0c8abbc36..3783850d8 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -294,12 +294,6 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
     eval(parse(text = exercise$global_setup), envir = envir)
   }
 
-
-  # Setup a temporary directory for rendering the exercise
-  exercise_dir <- tempfile(pattern = "lnr-ex")
-  dir.create(exercise_dir)
-  on.exit(unlink(exercise_dir), add = TRUE)
-
   checker_feedback <- NULL
   # Run the checker pre-evaluation _if_ there is code checking to do
   if (length(exercise$code_check)) {
@@ -317,6 +311,11 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
     }
   }
 
+  # Setup a temporary directory for rendering the exercise
+  exercise_dir <- tempfile(pattern = "lnr-ex")
+  dir.create(exercise_dir)
+  on.exit(unlink(exercise_dir), add = TRUE)
+
   # Resolve knitr options for the exercise and setup chunks
   rmd_results <- withr::with_dir(
     exercise_dir,

From bcd5dc3ba831bf44d255dc2643201610161dda32 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Wed, 23 Jun 2021 21:08:30 -0700
Subject: [PATCH 07/23] Use `local_dir()` instead of `with_dir()` in
 `evaluate_exercise()`

---
 R/exercise.R | 42 ++++++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 22 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 3783850d8..664841993 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -314,33 +314,31 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
   # Setup a temporary directory for rendering the exercise
   exercise_dir <- tempfile(pattern = "lnr-ex")
   dir.create(exercise_dir)
+  withr::local_dir(exercise_dir)
   on.exit(unlink(exercise_dir), add = TRUE)
 
   # Resolve knitr options for the exercise and setup chunks
-  rmd_results <- withr::with_dir(
-    exercise_dir,
-    tryCatch(
-      render_exercise(exercise, envir),
-      error = function(e) {
-        if (length(exercise$error_check)) {
-          # Run the condition through an error checker
-          # (the exercise could be to throw an error!)
-          checker_feedback <- try_checker(
-            exercise, "exercise.checker",
-            check_code = exercise$error_check,
-            envir_result = e$envir_result,
-            evaluate_result = e$evaluate_result,
-            envir_prep = e$envir_prep,
-            last_value = e$e,
-            engine = exercise$engine
-          )
-          if (is_exercise_result(checker_feedback)) {
-            return(checker_feedback)
-          }
+  rmd_results <- tryCatch(
+    render_exercise(exercise, envir),
+    error = function(e) {
+      if (length(exercise$error_check)) {
+        # Run the condition through an error checker
+        # (the exercise could be to throw an error!)
+        checker_feedback <- try_checker(
+          exercise, "exercise.checker",
+          check_code = exercise$error_check,
+          envir_result = e$envir_result,
+          evaluate_result = e$evaluate_result,
+          envir_prep = e$envir_prep,
+          last_value = e$e,
+          engine = exercise$engine
+        )
+        if (is_exercise_result(checker_feedback)) {
+          return(checker_feedback)
         }
-        exercise_result_error(e$msg)
       }
-    )
+      exercise_result_error(e$msg)
+    }
   )
 
   if (is_exercise_result(rmd_results)) {

From 18b0fa0d49904e621e6c91d94bb0993ce96a759f Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Thu, 24 Jun 2021 12:37:08 -0700
Subject: [PATCH 08/23] Simplify creation of tempdir

---
 R/exercise.R | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 664841993..c07233835 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -312,10 +312,8 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
   }
 
   # Setup a temporary directory for rendering the exercise
-  exercise_dir <- tempfile(pattern = "lnr-ex")
-  dir.create(exercise_dir)
+  exercise_dir <- withr::local_tempdir(pattern = "lrn-ex")
   withr::local_dir(exercise_dir)
-  on.exit(unlink(exercise_dir), add = TRUE)
 
   # Resolve knitr options for the exercise and setup chunks
   rmd_results <- tryCatch(

From 6e19e4adcee28e5f10f6f690130f9fa9b5810ad9 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Thu, 24 Jun 2021 15:03:19 -0700
Subject: [PATCH 09/23] Modify test to check `render_exercise()` and
 `evaluate_exercise()`

---
 R/exercise.R                   |  2 +-
 tests/testthat/test-exercise.R | 24 ++++++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index c07233835..babe362a6 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -328,7 +328,7 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
           envir_result = e$envir_result,
           evaluate_result = e$evaluate_result,
           envir_prep = e$envir_prep,
-          last_value = e$e,
+          last_value = e,
           engine = exercise$engine
         )
         if (is_exercise_result(checker_feedback)) {
diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index 78729396a..a22882c8c 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -140,16 +140,26 @@ test_that("render_exercise() returns identical envir_prep and envir_result if an
     error_check = "unevaluated, triggers error_check in render_exercise()"
   )
 
-  exercise_result <- withr::with_tempdir(
+  render_result <- withr::with_tempdir(
     rlang::catch_cnd(
       render_exercise(exercise, new.env()), "learnr_render_exercise_error"
     )
   )
+  expect_s3_class(render_result$last_value, "simpleError")
+  expect_equal(conditionMessage(render_result$last_value), "boom")
+  expect_identical(render_result$envir_prep, render_result$envir_result)
 
-  expect_s3_class(exercise_result$last_value, "simpleError")
-  expect_equal(conditionMessage(exercise_result$last_value), "boom")
-
-  expect_identical(exercise_result$envir_prep, exercise_result$envir_result)
+  eval_result <- evaluate_exercise(exercise, new.env())
+  expect_s3_class(
+    eval_result$feedback$checker_args$last_value, "learnr_render_exercise_error"
+  )
+  expect_equal(
+    eval_result$feedback$checker_args$last_value$error_message, "boom"
+  )
+  expect_identical(
+    eval_result$feedback$checker_args$envir_prep,
+    eval_result$feedback$checker_args$envir_result
+  )
 })
 
 test_that("render_exercise() returns envir_result up to error", {
@@ -171,7 +181,9 @@ test_that("render_exercise() returns envir_result up to error", {
   expect_s3_class(exercise_result$last_value, "simpleError")
   expect_equal(conditionMessage(exercise_result$last_value), "boom")
 
-  expect_false(identical(exercise_result$envir_prep, exercise_result$envir_result))
+  expect_false(
+    identical(exercise_result$envir_prep, exercise_result$envir_result)
+  )
   expect_setequal(ls(exercise_result$envir_prep), "x")
   expect_setequal(ls(exercise_result$envir_result), c("x", "y"))
   expect_identical(get("y", exercise_result$envir_result), 2)

From f04bdd4c5ff8a9680af34cc2c94b144e18f77157 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Fri, 25 Jun 2021 08:57:46 -0700
Subject: [PATCH 10/23] Fix bug in returning error message

---
 R/exercise.R | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/exercise.R b/R/exercise.R
index babe362a6..52dc2e127 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -335,7 +335,7 @@ evaluate_exercise <- function(exercise, envir, evaluate_global_setup = FALSE) {
           return(checker_feedback)
         }
       }
-      exercise_result_error(e$msg)
+      exercise_result_error(e$error_message)
     }
   )
 

From ea1675b379fe0d48cb204188f28641cd1a86dd21 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Fri, 25 Jun 2021 08:58:03 -0700
Subject: [PATCH 11/23] Update tests of `render_exercise()` and transfer tests
 to `evaluate_exercise()`

---
 tests/testthat/test-exercise.R | 36 +++++++---------------------------
 1 file changed, 7 insertions(+), 29 deletions(-)

diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index a22882c8c..8914dd42f 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -148,18 +148,7 @@ test_that("render_exercise() returns identical envir_prep and envir_result if an
   expect_s3_class(render_result$last_value, "simpleError")
   expect_equal(conditionMessage(render_result$last_value), "boom")
   expect_identical(render_result$envir_prep, render_result$envir_result)
-
-  eval_result <- evaluate_exercise(exercise, new.env())
-  expect_s3_class(
-    eval_result$feedback$checker_args$last_value, "learnr_render_exercise_error"
-  )
-  expect_equal(
-    eval_result$feedback$checker_args$last_value$error_message, "boom"
-  )
-  expect_identical(
-    eval_result$feedback$checker_args$envir_prep,
-    eval_result$feedback$checker_args$envir_result
-  )
+  expect_equal(get("x", render_result$envir_prep), 1)
 })
 
 test_that("render_exercise() returns envir_result up to error", {
@@ -189,30 +178,19 @@ test_that("render_exercise() returns envir_result up to error", {
   expect_identical(get("y", exercise_result$envir_result), 2)
 })
 
-test_that("render_exercise() with errors and no checker returns exercise result error", {
+test_that("evaluate_exercise() with errors and no checker includes exercise result error", {
   exercise <- mock_exercise(
     user_code = "stop('user')",
     chunks = list(mock_chunk("setup-1", "stop('setup')")),
     setup_label = "setup-1"
   )
-
-  exercise_result <- withr::with_tempdir(
-    rlang::catch_cnd(
-      render_exercise(exercise, new.env()), "learnr_render_exercise_error"
-    )
-  )
-  expect_s3_class(exercise_result, "learnr_render_exercise_error")
-  expect_identical(exercise_result$error_message, "setup")
+  exercise_result <- evaluate_exercise(exercise, new.env())
+  expect_equal(exercise_result$error_message, "setup")
   expect_null(exercise_result$feedback)
 
-  exercise <- mock_exercise(user_code = "stop('user')")
-  exercise_result <- withr::with_tempdir(
-    rlang::catch_cnd(
-      render_exercise(exercise, new.env()), "learnr_render_exercise_error"
-    )
-  )
-  expect_s3_class(exercise_result, "learnr_render_exercise_error")
-  expect_identical(exercise_result$error_message, "user")
+  exercise        <- mock_exercise(user_code = "stop('user')")
+  exercise_result <- evaluate_exercise(exercise, new.env())
+  expect_equal(exercise_result$error_message, "user")
   expect_null(exercise_result$feedback)
 })
 

From 939eda6990178a9e02ecd44f625344fb6328866e Mon Sep 17 00:00:00 2001
From: rossellhayes <rossellhayes@users.noreply.github.com>
Date: Fri, 9 Jul 2021 15:45:24 +0000
Subject: [PATCH 12/23] Build docs (GitHub Actions)

---
 docs/examples.html                              |  1 -
 docs/exercises.html                             |  1 -
 docs/formats.html                               |  1 -
 docs/index.html                                 |  1 -
 docs/publishing.html                            |  3 +--
 docs/questions.html                             |  1 -
 docs/site_libs/header-attrs-2.9/header-attrs.js | 12 ------------
 7 files changed, 1 insertion(+), 19 deletions(-)
 delete mode 100644 docs/site_libs/header-attrs-2.9/header-attrs.js

diff --git a/docs/examples.html b/docs/examples.html
index 16f6fc61b..bfc81bf36 100644
--- a/docs/examples.html
+++ b/docs/examples.html
@@ -13,7 +13,6 @@
 
 <title>Examples</title>
 
-<script src="site_libs/header-attrs-2.9/header-attrs.js"></script>
 <script src="site_libs/jquery-1.11.3/jquery.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <link href="site_libs/bootstrap-3.3.5/css/cosmo.min.css" rel="stylesheet" />
diff --git a/docs/exercises.html b/docs/exercises.html
index 458449eb7..96c6da82e 100644
--- a/docs/exercises.html
+++ b/docs/exercises.html
@@ -13,7 +13,6 @@
 
 <title>Exercises</title>
 
-<script src="site_libs/header-attrs-2.9/header-attrs.js"></script>
 <script src="site_libs/jquery-1.11.3/jquery.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <link href="site_libs/bootstrap-3.3.5/css/cosmo.min.css" rel="stylesheet" />
diff --git a/docs/formats.html b/docs/formats.html
index ae228d1c4..6f0c838d5 100644
--- a/docs/formats.html
+++ b/docs/formats.html
@@ -13,7 +13,6 @@
 
 <title>Formats</title>
 
-<script src="site_libs/header-attrs-2.9/header-attrs.js"></script>
 <script src="site_libs/jquery-1.11.3/jquery.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <link href="site_libs/bootstrap-3.3.5/css/cosmo.min.css" rel="stylesheet" />
diff --git a/docs/index.html b/docs/index.html
index 3694d276c..34d538b24 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -13,7 +13,6 @@
 
 <title>Interactive Tutorials for R</title>
 
-<script src="site_libs/header-attrs-2.9/header-attrs.js"></script>
 <script src="site_libs/jquery-1.11.3/jquery.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <link href="site_libs/bootstrap-3.3.5/css/cosmo.min.css" rel="stylesheet" />
diff --git a/docs/publishing.html b/docs/publishing.html
index 22a84bb23..9e98abc7a 100644
--- a/docs/publishing.html
+++ b/docs/publishing.html
@@ -13,7 +13,6 @@
 
 <title>Publishing</title>
 
-<script src="site_libs/header-attrs-2.9/header-attrs.js"></script>
 <script src="site_libs/jquery-1.11.3/jquery.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <link href="site_libs/bootstrap-3.3.5/css/cosmo.min.css" rel="stylesheet" />
@@ -388,7 +387,7 @@ <h2>R Package</h2>
 <pre class="r"><code>install.packages(&quot;learnr&quot;)
 learnr::run_tutorial(&quot;introduction&quot;, package = &quot;mypackage&quot;)</code></pre>
 <div id="exercise-checkers" class="section level3 toc-ignore">
-<h3 class="toc-ignore">Exercise Checkers</h3>
+<h3>Exercise Checkers</h3>
 <p>Note that if your tutorial performs <a href="exercises.html#checking-exercises">exercise checking</a> via an external package then you should be sure to add the package you use for checking as an <code>Imports</code> dependency of your package so it’s installed automatically along with your package.</p>
 <p>Note that it’s likely that the <strong>learnr</strong> package will eventually include or depend on another package that provides checking functions. For the time being though explicit installation of external checking packages is a requirement.</p>
 </div>
diff --git a/docs/questions.html b/docs/questions.html
index b7e1498bb..5f5c1c672 100644
--- a/docs/questions.html
+++ b/docs/questions.html
@@ -13,7 +13,6 @@
 
 <title>Questions</title>
 
-<script src="site_libs/header-attrs-2.9/header-attrs.js"></script>
 <script src="site_libs/jquery-1.11.3/jquery.min.js"></script>
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <link href="site_libs/bootstrap-3.3.5/css/cosmo.min.css" rel="stylesheet" />
diff --git a/docs/site_libs/header-attrs-2.9/header-attrs.js b/docs/site_libs/header-attrs-2.9/header-attrs.js
deleted file mode 100644
index dd57d92e0..000000000
--- a/docs/site_libs/header-attrs-2.9/header-attrs.js
+++ /dev/null
@@ -1,12 +0,0 @@
-// Pandoc 2.9 adds attributes on both header and div. We remove the former (to
-// be compatible with the behavior of Pandoc < 2.8).
-document.addEventListener('DOMContentLoaded', function(e) {
-  var hs = document.querySelectorAll("div.section[class*='level'] > :first-child");
-  var i, h, a;
-  for (i = 0; i < hs.length; i++) {
-    h = hs[i];
-    if (!/^h[1-6]$/i.test(h.tagName)) continue;  // it should be a header h1-h6
-    a = h.attributes;
-    while (a.length > 0) h.removeAttribute(a[0].name);
-  }
-});

From c0ba8a1d4d31431ac9d691e0b66f8b8cdaa0a288 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 12:13:59 -0400
Subject: [PATCH 13/23] Restore data directory feature

---
 R/exercise.R | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/R/exercise.R b/R/exercise.R
index 22f12f3c8..ce2bed9e8 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -327,6 +327,11 @@ evaluate_exercise <- function(
 
   # Setup a temporary directory for rendering the exercise
   exercise_dir <- withr::local_tempdir(pattern = "lrn-ex")
+
+  # Copy files from data directory into exercise
+  copy_data_dir(data_dir, exercise_dir)
+
+  # Move into the temp exercise directory for evaluation and checking
   withr::local_dir(exercise_dir)
 
   # Resolve knitr options for the exercise and setup chunks

From f56e82e0865b794a63d2086d7ec51629d9d6c138 Mon Sep 17 00:00:00 2001
From: Alex Rossell Hayes <alexander@rossellhayes.com>
Date: Fri, 9 Jul 2021 09:22:22 -0700
Subject: [PATCH 14/23] Fix merge conflict

---
 R/exercise.R | 49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 22f12f3c8..948d4d7a0 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -326,31 +326,38 @@ evaluate_exercise <- function(
   }
 
   # Setup a temporary directory for rendering the exercise
-  exercise_dir <- withr::local_tempdir(pattern = "lrn-ex")
-  withr::local_dir(exercise_dir)
+  exercise_dir <- tempfile(pattern = "lnr-ex")
+  dir.create(exercise_dir)
+  on.exit(unlink(exercise_dir), add = TRUE)
+
+  # Copy files from data directory into exercise
+  copy_data_dir(data_dir, exercise_dir)
 
   # Resolve knitr options for the exercise and setup chunks
-  rmd_results <- tryCatch(
-    render_exercise(exercise, envir),
-    error = function(e) {
-      if (length(exercise$error_check)) {
-        # Run the condition through an error checker
-        # (the exercise could be to throw an error!)
-        checker_feedback <- try_checker(
-          exercise, "exercise.checker",
-          check_code = exercise$error_check,
-          envir_result = e$envir_result,
-          evaluate_result = e$evaluate_result,
-          envir_prep = e$envir_prep,
-          last_value = e,
-          engine = exercise$engine
-        )
-        if (is_exercise_result(checker_feedback)) {
-          return(checker_feedback)
+  rmd_results <- withr::with_dir(
+    exercise_dir,
+    tryCatch(
+      render_exercise(exercise, envir),
+      error = function(e) {
+        if (length(exercise$error_check)) {
+          # Run the condition through an error checker
+          # (the exercise could be to throw an error!)
+          checker_feedback <- try_checker(
+            exercise, "exercise.checker",
+            check_code = exercise$error_check,
+            envir_result = e$envir_result,
+            evaluate_result = e$evaluate_result,
+            envir_prep = e$envir_prep,
+            last_value = e,
+            engine = exercise$engine
+          )
+          if (is_exercise_result(checker_feedback)) {
+            return(checker_feedback)
+          }
         }
+        exercise_result_error(e$error_message)
       }
-      exercise_result_error(e$error_message)
-    }
+    )
   )
 
   if (is_exercise_result(rmd_results)) {

From c0149cf4364f5ee4f7f202bb2a73f8a77073f0a7 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 12:36:47 -0400
Subject: [PATCH 15/23] Restore withr::local_tempdir()

---
 R/exercise.R | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 68579be30..ce2bed9e8 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -326,9 +326,7 @@ evaluate_exercise <- function(
   }
 
   # Setup a temporary directory for rendering the exercise
-  exercise_dir <- tempfile(pattern = "lnr-ex")
-  dir.create(exercise_dir)
-  on.exit(unlink(exercise_dir), add = TRUE)
+  exercise_dir <- withr::local_tempdir(pattern = "lrn-ex")
 
   # Copy files from data directory into exercise
   copy_data_dir(data_dir, exercise_dir)

From 3365c8ec38302de5ec779eb293a73463172f9313 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 12:44:39 -0400
Subject: [PATCH 16/23] Fix comment about purpose of render_exercise()

---
 R/exercise.R | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/exercise.R b/R/exercise.R
index ce2bed9e8..459ab5874 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -334,7 +334,7 @@ evaluate_exercise <- function(
   # Move into the temp exercise directory for evaluation and checking
   withr::local_dir(exercise_dir)
 
-  # Resolve knitr options for the exercise and setup chunks
+  # Evaluate the submitted code by rendering the exercise in a special .Rmd
   rmd_results <- tryCatch(
     render_exercise(exercise, envir),
     error = function(e) {

From c5e8a892e352b1e675b89b712f68b70e31ab9eab Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 12:47:15 -0400
Subject: [PATCH 17/23] Rename error object in render_exercise error

---
 R/exercise.R | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 459ab5874..fcd1e0c8f 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -337,24 +337,24 @@ evaluate_exercise <- function(
   # Evaluate the submitted code by rendering the exercise in a special .Rmd
   rmd_results <- tryCatch(
     render_exercise(exercise, envir),
-    error = function(e) {
+    error = function(err_render) {
       if (length(exercise$error_check)) {
         # Run the condition through an error checker
         # (the exercise could be to throw an error!)
         checker_feedback <- try_checker(
           exercise, "exercise.checker",
           check_code = exercise$error_check,
-          envir_result = e$envir_result,
-          evaluate_result = e$evaluate_result,
-          envir_prep = e$envir_prep,
-          last_value = e,
+          envir_result = err_render$envir_result,
+          evaluate_result = err_render$evaluate_result,
+          envir_prep = err_render$envir_prep,
+          last_value = err_render,
           engine = exercise$engine
         )
         if (is_exercise_result(checker_feedback)) {
           return(checker_feedback)
         }
       }
-      exercise_result_error(e$error_message)
+      exercise_result_error(err_render$error_message)
     }
   )
 

From ee19db24ce06684c3d0882d02f5ccbe5c9af01fc Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 13:14:06 -0400
Subject: [PATCH 18/23] Add test for exercises that exceed the timelimt

---
 R/exercise.R                   |  1 +
 tests/testthat/test-exercise.R | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/R/exercise.R b/R/exercise.R
index fcd1e0c8f..fab8c12dd 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -595,6 +595,7 @@ render_exercise <- function(exercise, envir) {
   })
 
   if (is_exercise_result(output_file)) {
+    # this only happens when the render result is a timeout error
     return(output_file)
   }
 
diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index 54d33f7b7..9d8a9d36d 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -764,3 +764,29 @@ test_that("env vars are protected from both user and author modification", {
   # evaluate_exercise() restores the TEST option after checking too
   expect_equal(res$after_eval, "APP")
 })
+
+
+# Timelimit ---------------------------------------------------------------
+
+test_that("Exercise timelimit error is returned when exercise takes too long", {
+  skip_on_cran()
+
+  ex <- mock_exercise(user_code = "Sys.sleep(3)", exercise.timelimit = 1)
+
+  make_evaluator <- setup_forked_evaluator_factory(max_forked_procs = 1)
+  evaluator <- make_evaluator(
+    evaluate_exercise(ex, new.env()),
+    timelimit = ex$options$exercise.timelimit
+  )
+
+  evaluator$start()
+  while (!evaluator$completed()) {
+    Sys.sleep(1)
+  }
+  res <- evaluator$result()
+
+  expect_s3_class(res, "learnr_exercise_result")
+  expect_true(res$timeout_exceeded)
+  expect_match(res$error_message, "permitted timelimit")
+  expect_match(as.character(res$html_output), "alert-danger")
+})

From 9dab33ffbd45d7c3f472161a385fcca781afcd61 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 13:31:23 -0400
Subject: [PATCH 19/23] More specific tests for presence of error_check code

---
 R/exercise.R | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index fab8c12dd..441ecf787 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -338,9 +338,9 @@ evaluate_exercise <- function(
   rmd_results <- tryCatch(
     render_exercise(exercise, envir),
     error = function(err_render) {
-      if (length(exercise$error_check)) {
-        # Run the condition through an error checker
-        # (the exercise could be to throw an error!)
+      if (!is.null(exercise$error_check) && any(nzchar(exercise$error_check))) {
+        # Check the error thrown by the submitted code when there's error
+        # checking: the exercise could be to throw an error!
         checker_feedback <- try_checker(
           exercise, "exercise.checker",
           check_code = exercise$error_check,

From bd095bade35bdcf2dea1aa30b2435f8a1a42e0b1 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 15:26:19 -0400
Subject: [PATCH 20/23] Standardize exercise checking-related code to length-1
 string

---
 R/exercise.R                   | 31 ++++++++++++++++++++++++-------
 tests/testthat/test-exercise.R | 20 ++++++++++++++++++++
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 441ecf787..3609e3557 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -264,7 +264,7 @@ upgrade_exercise <- function(exercise, require_items = NULL) {
 # returns NULL if everything is okay, otherwise a character string describing
 # the reason the validation check failed.
 validate_exercise <- function(exercise, require_items = NULL) {
-required_names <- c("code", "label", "options", "chunks", require_items)
+  required_names <- c("code", "label", "options", "chunks", require_items)
   missing_names <- setdiff(required_names, names(exercise))
   if (length(missing_names)) {
     return(paste("Missing exercise items:", paste(missing_names, collapse = ", ")))
@@ -273,6 +273,20 @@ required_names <- c("code", "label", "options", "chunks", require_items)
   NULL
 }
 
+standardize_exercise_code <- function(exercise) {
+  for (type in c("error_check", "code_check", "check", "code", "global_setup")) {
+    if (inherits(exercise[[type]], "AsIs")) {
+      next
+    }
+    if (is.null(exercise[[type]]) || !length(exercise[[type]])) {
+      exercise[[type]] <- ""
+      next
+    }
+    exercise[[type]] <- str_trim(paste0(exercise[[type]], collapse = "\n"))
+  }
+  exercise
+}
+
 # evaluate an exercise and return a list containing output and dependencies
 # @param evaluate_global_setup - If `FALSE`, will not evaluate the global setup
 #   code. Instead, it just concatenates the exercise- specific setup code and
@@ -295,11 +309,14 @@ evaluate_exercise <- function(
     require_items = if (evaluate_global_setup) "global_setup"
   )
 
+  # standardize exercise code to single string (code, *check, global_setup)
+  exercise <- standardize_exercise_code(exercise)
+
   i18n_set_language_option(exercise$tutorial$language)
 
   # return immediately and clear visible results
   # do not consider this an exercise submission
-  if (!nzchar(str_trim(paste0(exercise$code, collapse = "\n")))) {
+  if (!nzchar(exercise$code)) {
     # " " since html_output needs to pass a req()
     return(exercise_result(html_output = " "))
   }
@@ -309,8 +326,8 @@ evaluate_exercise <- function(
   }
 
   checker_feedback <- NULL
-  # Run the checker pre-evaluation _if_ there is code checking to do
-  if (length(exercise$code_check)) {
+  # Check the code pre-evaluation, if code_check is provided
+  if (nzchar(exercise$code_check)) {
     checker_feedback <- try_checker(
       exercise, "exercise.checker",
       check_code = exercise$code_check,
@@ -338,7 +355,7 @@ evaluate_exercise <- function(
   rmd_results <- tryCatch(
     render_exercise(exercise, envir),
     error = function(err_render) {
-      if (!is.null(exercise$error_check) && any(nzchar(exercise$error_check))) {
+      if (nzchar(exercise$error_check)) {
         # Check the error thrown by the submitted code when there's error
         # checking: the exercise could be to throw an error!
         checker_feedback <- try_checker(
@@ -363,7 +380,7 @@ evaluate_exercise <- function(
   }
 
   # Run the checker post-evaluation (for checking code results)
-  if (length(exercise$check)) {
+  if (nzchar(exercise$check)) {
     checker_feedback <- try_checker(
       exercise, "exercise.checker",
       check_code = exercise$check,
@@ -375,7 +392,7 @@ evaluate_exercise <- function(
     )
   }
 
-  # include any checker feedback with the exercise results
+  # Return checker feedback (if any) with the exercise results
   exercise_result(
     feedback = checker_feedback$feedback,
     html_output = rmd_results$html_output
diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index 9d8a9d36d..d7395cdea 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -321,6 +321,26 @@ test_that("serialized exercises produce equivalent evaluate_exercise() results",
   )
 })
 
+test_that("standardize_exercise_result() ensures top-level code is length-1 string", {
+  ex <- standardize_exercise_code(
+    list(
+      code = c("a", "b"),
+      check = character(),
+      code_check = c("  ", "  ", "\t\t\t"),
+      global_setup = c(
+        "",
+        "def return_one():",
+        "\treturn 1",
+        ""
+      )
+    )
+  )
+
+  expect_equal(ex$code, "a\nb")
+  expect_equal(ex$check, "")
+  expect_equal(ex$code_check, "")
+  expect_equal(ex$global_setup, "def return_one():\n\treturn 1")
+})
 
 # exercise_result() -------------------------------------------------------
 

From a4030f05048f40118b825507ed199ca5dae7cac7 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 15:48:30 -0400
Subject: [PATCH 21/23] Skip timelimit test on windows

---
 tests/testthat/test-exercise.R | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/testthat/test-exercise.R b/tests/testthat/test-exercise.R
index d7395cdea..d11dd0988 100644
--- a/tests/testthat/test-exercise.R
+++ b/tests/testthat/test-exercise.R
@@ -790,6 +790,7 @@ test_that("env vars are protected from both user and author modification", {
 
 test_that("Exercise timelimit error is returned when exercise takes too long", {
   skip_on_cran()
+  skip_on_os("windows")
 
   ex <- mock_exercise(user_code = "Sys.sleep(3)", exercise.timelimit = 1)
 

From be678f45253f432bd17fe9a27670c86dc67bf253 Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 16:24:17 -0400
Subject: [PATCH 22/23] Factor out `standardize_code()`

We may want to use it in other places
---
 R/exercise.R | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/R/exercise.R b/R/exercise.R
index 3609e3557..901b1c423 100644
--- a/R/exercise.R
+++ b/R/exercise.R
@@ -273,17 +273,19 @@ validate_exercise <- function(exercise, require_items = NULL) {
   NULL
 }
 
-standardize_exercise_code <- function(exercise) {
-  for (type in c("error_check", "code_check", "check", "code", "global_setup")) {
-    if (inherits(exercise[[type]], "AsIs")) {
-      next
-    }
-    if (is.null(exercise[[type]]) || !length(exercise[[type]])) {
-      exercise[[type]] <- ""
-      next
-    }
-    exercise[[type]] <- str_trim(paste0(exercise[[type]], collapse = "\n"))
+standardize_code <- function(code) {
+  if (inherits(code, "AsIs")) {
+    return(code)
+  }
+  if (is.null(code) || !length(code)) {
+    return("")
   }
+  str_trim(paste0(code, collapse = "\n"))
+}
+
+standardize_exercise_code <- function(exercise) {
+  ex_code_items <- c("error_check", "code_check", "check", "code", "global_setup")
+  exercise[ex_code_items] <- lapply(exercise[ex_code_items], standardize_code)
   exercise
 }
 

From 287aca3cf79fa3facdf41c87f6c3854a261e42ac Mon Sep 17 00:00:00 2001
From: Garrick Aden-Buie <garrick@adenbuie.com>
Date: Fri, 9 Jul 2021 16:26:53 -0400
Subject: [PATCH 23/23] Add NEWS item

---
 NEWS.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS.md b/NEWS.md
index 9268171e8..1cfccdc45 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -47,6 +47,7 @@ learnr (development version)
 * `exercise_result()` no longer combines the code output and feedback; this now happens just before presenting the exercise result to the user ([#522](https://github.com/rstudio/learnr/pull/522)).
 * Correct/incorrect question markers are now configurable via CSS. You can change or style these markers using the `.tutorial-question .question-final .correct::before` and `.tutorial-qusetion .question-final .incorrect::before` selectors. A new helper function, `finalize_question()`, can be used to apply the `.question-final` class to custom learnr questions. ([#531](https://github.com/rstudio/learnr/pull/531))
 * `options()` and environment variables are now reset after rendering exercises so changes made by user input or checking code cannot affect other exercises. ([#542](https://github.com/rstudio/learnr/pull/542))
+* Exercise checking is now conducted in the same temporary directory where exercises are evaluated. ([#544](https://github.com/rstudio/learnr/pull/544/))
 
 ## Bug fixes