From 98fdf1aeab081146c5be4c85103bb311ca5a8203 Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Sat, 24 Sep 2022 08:17:44 -0500
Subject: [PATCH] Improve capture_output() encoding handling (#1693)

Fixes #1574
---
 NEWS.md                                |  3 +++
 R/capture-output.R                     |  5 ++++-
 tests/testthat/test-capture-output.R   | 20 ++++++++++++++++++++
 tests/testthat/test-evaluate-promise.R | 13 -------------
 4 files changed, 27 insertions(+), 14 deletions(-)
 create mode 100644 tests/testthat/test-capture-output.R

diff --git a/NEWS.md b/NEWS.md
index 41b421523..6bb88384e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # testthat (development version)
 
+* Improve way `capture_output()` handles encoding thanks to suggestion from
+  Kurt Hornik.
+
 * `test_check()` now suppresses hyperlinks since they'll take you to the wrong
   places (#1648).
 
diff --git a/R/capture-output.R b/R/capture-output.R
index 0f868543c..66da46f07 100644
--- a/R/capture-output.R
+++ b/R/capture-output.R
@@ -47,15 +47,18 @@ eval_with_output <- function(code, print = FALSE, width = 80) {
   if (!is.null(width)) {
     local_width(width)
   }
+
   result <- withr::with_output_sink(path, withVisible(code))
   if (result$visible && print) {
     withr::with_output_sink(path, testthat_print(result$value), append = TRUE)
   }
 
+  # A sink() will always write in the native encoding, so we read with
+  # base::readLines() then convert to UTF-8
   list(
     val = result$value,
     vis = result$visible,
-    out = brio::read_lines(path)
+    out = enc2utf8(base::readLines(path, warn = FALSE))
   )
 }
 
diff --git a/tests/testthat/test-capture-output.R b/tests/testthat/test-capture-output.R
new file mode 100644
index 000000000..d1d967f1b
--- /dev/null
+++ b/tests/testthat/test-capture-output.R
@@ -0,0 +1,20 @@
+test_that("multiplication works", {
+  utf8 <- "M\u00e4chler"
+  latin1 <- "M\xe4chler"
+  Encoding(latin1) <- "latin1"
+
+  expect_equal(capture_output_lines(cat(latin1)), utf8)
+})
+
+test_that("capture output captures output", {
+  out1 <- capture_output(print(1:5))
+  out2 <- capture_output(1:5, print = TRUE)
+
+  expect_equal(out1, "[1] 1 2 3 4 5")
+  expect_equal(out2, "[1] 1 2 3 4 5")
+})
+
+test_that("capture output doesn't print invisible things", {
+  out <- capture_output(invisible(1), print = TRUE)
+  expect_equal(out, "")
+})
diff --git a/tests/testthat/test-evaluate-promise.R b/tests/testthat/test-evaluate-promise.R
index 2f90f572e..d5d95c887 100644
--- a/tests/testthat/test-evaluate-promise.R
+++ b/tests/testthat/test-evaluate-promise.R
@@ -25,16 +25,3 @@ test_that("capture_messages captures messages", {
   })
   expect_equal(out, c("a\n", "b\n")) # message adds LF by default
 })
-
-test_that("capture output captures output", {
-  out1 <- capture_output(print(1:5))
-  out2 <- capture_output(1:5, print = TRUE)
-
-  expect_equal(out1, "[1] 1 2 3 4 5")
-  expect_equal(out2, "[1] 1 2 3 4 5")
-})
-
-test_that("capture output doesn't print invisible things", {
-  out <- capture_output(invisible(1), print = TRUE)
-  expect_equal(out, "")
-})