1 files changed, 16 insertions, 0 deletions
diff --git a/tests/test_build_htmlhelp.py b/tests/test_build_htmlhelp.py
index 124462aa5..43f5788a1 100644
--- a/tests/test_build_htmlhelp.py
+++ b/tests/test_build_htmlhelp.py
@@ -8,6 +8,8 @@
     :license: BSD, see LICENSE for details.
 """
 
+import re
+
 import pytest
 
 from sphinx.builders.htmlhelp import default_htmlhelp_basename
@@ -29,3 +31,17 @@ def test_default_htmlhelp_basename():
     config = Config({'project': 'Sphinx Documentation'})
     config.init_values()
     assert default_htmlhelp_basename(config) == 'sphinxdoc'
+
+
+@pytest.mark.sphinx('htmlhelp', testroot='build-htmlhelp')
+def test_chm(app):
+    app.build()
+
+    # check .hhk file
+    outname = app.builder.config.htmlhelp_basename
+    hhk_path = str(app.outdir / outname + '.hhk')
+
+    with open(hhk_path, 'rb') as f:
+        data = f.read()
+    m = re.search(br'&#[xX][0-9a-fA-F]+;', data)
+    assert m is None, 'Hex escaping exists in .hhk file: ' + str(m.group(0))