diff --git a/R/utils.R b/R/utils.R
index a4f624ce2..88e13c151 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -80,7 +80,9 @@ write_if_different <- function(path, contents, check = TRUE) {
     FALSE
   } else {
     cat(sprintf('Writing %s\n', name))
-    writeLines(contents, path)
+    con <- file(path, encoding = "UTF-8")
+    on.exit(close(con), add = TRUE)
+    writeLines(contents, con)
     TRUE
   }
 }
diff --git a/tests/testthat/test-nonASCII.R b/tests/testthat/test-nonASCII.R
index f7af5d3b2..eeb24167d 100644
--- a/tests/testthat/test-nonASCII.R
+++ b/tests/testthat/test-nonASCII.R
@@ -8,6 +8,9 @@ test_that("can generate nonASCII document", {
   expect_true(file.exists(file.path(test_pkg, "man", "printChineseMsg.Rd")))
 
   cnChar <- readLines(file.path(test_pkg, "man", "printChineseMsg.Rd"), encoding = "UTF-8")
-  expect_true(any(grepl("我爱中文", cnChar)) && any(grepl("中文注释", cnChar)))
 
+  # Because the parse in testthat::test don't specify encoding to UTF-8 as well,
+  # so we have to use unicode escapes.
+  expect_true(any(grepl("\u6211\u7231\u4e2d\u6587", cnChar)))
+  expect_true(any(grepl("\u4e2d\u6587\u6ce8\u91ca", cnChar)))
 })