diff --git a/testing/web-platform/tests/encoding/sniffing.html b/testing/web-platform/tests/encoding/sniffing.html
new file mode 100644
index 0000000000000..6f5955441d44a
--- /dev/null
+++ b/testing/web-platform/tests/encoding/sniffing.html
@@ -0,0 +1,137 @@
+<
+!
+doctype
+html
+>
+<
+script
+src
+=
+/
+resources
+/
+testharness
+.
+js
+>
+<
+/
+script
+>
+<
+script
+src
+=
+/
+resources
+/
+testharnessreport
+.
+js
+>
+<
+/
+script
+>
+<
+title
+>
+No
+(
+UTF
+-
+8
+)
+sniffing
+allowed
+<
+/
+title
+>
+<
+div
+id
+=
+log
+>
+<
+/
+div
+>
+<
+div
+id
+=
+content
+>
+Hello
+World
+!
+<
+/
+div
+>
+<
+script
+>
+test
+(
+(
+)
+=
+>
+{
+assert_equals
+(
+document
+.
+getElementById
+(
+"
+content
+"
+)
+.
+textContent
+"
+\
+u00C2
+\
+u20AC
+\
+u00C2
+\
+u20AC
+Hello
+World
+!
+\
+u00C2
+\
+u20AC
+\
+u00C2
+\
+u20AC
+"
+)
+;
+assert_equals
+(
+document
+.
+characterSet
+"
+windows
+-
+1252
+"
+)
+;
+}
+)
+;
+<
+/
+script
+>