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diff --git a/testing/web-platform/tests/encoding/api-surrogates-utf8.html b/testing/web-platform/tests/encoding/api-surrogates-utf8.html
new file mode 100644
index 000000000..ef0ad4075
--- /dev/null
+++ b/testing/web-platform/tests/encoding/api-surrogates-utf8.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+<title>Encoding API: Invalid UTF-16 surrogates with UTF-8 encoding</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+
+var badStrings = [
+    {
+        input: 'abc123',
+        expected: [0x61, 0x62, 0x63, 0x31, 0x32, 0x33],
+        decoded: 'abc123',
+        name: 'Sanity check'
+    },
+    {
+        input: '\uD800',
+        expected: [0xef, 0xbf, 0xbd],
+        decoded: '\uFFFD',
+        name: 'Surrogate half (low)'
+    },
+    {
+        input: '\uDC00',
+        expected: [0xef, 0xbf, 0xbd],
+        decoded: '\uFFFD',
+        name: 'Surrogate half (high)'
+    },
+    {
+        input: 'abc\uD800123',
+        expected: [0x61, 0x62, 0x63, 0xef, 0xbf, 0xbd, 0x31, 0x32, 0x33],
+        decoded: 'abc\uFFFD123',
+        name: 'Surrogate half (low), in a string'
+    },
+    {
+        input: 'abc\uDC00123',
+        expected: [0x61, 0x62, 0x63, 0xef, 0xbf, 0xbd, 0x31, 0x32, 0x33],
+        decoded: 'abc\uFFFD123',
+        name: 'Surrogate half (high), in a string'
+    },
+    {
+        input: '\uDC00\uD800',
+        expected: [0xef, 0xbf, 0xbd, 0xef, 0xbf, 0xbd],
+        decoded: '\uFFFD\uFFFD',
+        name: 'Wrong order'
+    }
+];
+
+badStrings.forEach(function(t) {
+    test(function() {
+        var encoded = new TextEncoder().encode(t.input);
+        assert_array_equals([].slice.call(encoded), t.expected);
+        assert_equals(new TextDecoder('utf-8').decode(encoded), t.decoded);
+    }, 'Invalid surrogates encoded into UTF-8: ' + t.name);
+});
+
+</script>