diff --git a/DESCRIPTION b/DESCRIPTION
index 93d7d373..51775bcd 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: bookdown
 Type: Package
 Title: Authoring Books and Technical Documents with R Markdown
-Version: 0.45
+Version: 0.45.2
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Christophe", "Dervieux", , "cderv@posit.co", role = c("ctb"),
diff --git a/NEWS.md b/NEWS.md
index faca4c62..951853be 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# CHANGES IN bookdown VERSION 0.46
+
+- Removed tests for `xfun::with_ext()` that don't belong to this package.
+
 # CHANGES IN bookdown VERSION 0.45
 
 - `gitbook()` TOC now works again with Pandoc 3.2.1 and above (thanks, @privefl, #1503).
diff --git a/tests/testit/test-utils.R b/tests/testit/test-utils.R
index b160f38e..45b51c13 100644
--- a/tests/testit/test-utils.R
+++ b/tests/testit/test-utils.R
@@ -1,31 +1,8 @@
 library(testit)
 
-1 %==% 1
-
-assert(
-  'next_nearest() works',
-  next_nearest(c(1, 4, 8), 1:9) %==% c(2L, 5L, 9L)
-)
-
-assert(
-  'with_ext() works',
-  with_ext(NULL, 'a') %==% NULL,
-  with_ext('a', NULL) %==% 'a',
-  with_ext('a', 'bcd') %==% 'a.bcd',
-  with_ext('a.html', '') %==% 'a',
-  with_ext('a.html', 'tex') %==% 'a.tex',
-  with_ext('a.html', '.tex') %==% 'a.tex',
-  with_ext(c('a', 'b', 'c'), 'css') %==% c('a.css', 'b.css', 'c.css'),
-  with_ext(c('a.html', 'b', 'c.js'), 'css') %==% c('a.css', 'b.css', 'c.css'),
-  with_ext(c('a.html', 'b', 'c'), '.css') %==% c('a.css', 'b.css', 'c.css'),
-  with_ext('a', c('css', '.html')) %==% c('a.css', 'a.html'),
-  with_ext(c('a.doc', 'b.gz', 'c'), c('css', '.tar', '.png')) %==% c('a.css', 'b.tar', 'c.png')
-)
-
-assert(
-  'with_ext() signals an error when length(x) != length(ext)',
-  has_error(with_ext(c('a', 'b.css'), c('foo', 'bar', 'ham')))
-)
+assert('next_nearest() works', {
+  (next_nearest(c(1, 4, 8), 1:9) %==% c(2L, 5L, 9L))
+})
 
 assert('clean_meta_tags() cleans HTML inside <meta>', {
   (clean_meta_tags('<meta name="foo" content="hi text">') %==%