1 files changed, 46 insertions, 0 deletions
diff --git a/testing/web-platform/tests/encoding/textencoder-utf16-surrogates.any.js b/testing/web-platform/tests/encoding/textencoder-utf16-surrogates.any.js
new file mode 100644
index 0000000000..014a0ebb12
--- /dev/null
+++ b/testing/web-platform/tests/encoding/textencoder-utf16-surrogates.any.js
@@ -0,0 +1,46 @@
+// META: title=Encoding API: USVString surrogate handling when encoding
+
+var bad = [
+    {
+        input: '\uD800',
+        expected: '\uFFFD',
+        name: 'lone surrogate lead'
+    },
+    {
+        input: '\uDC00',
+        expected: '\uFFFD',
+        name: 'lone surrogate trail'
+    },
+    {
+        input: '\uD800\u0000',
+        expected: '\uFFFD\u0000',
+        name: 'unmatched surrogate lead'
+    },
+    {
+        input: '\uDC00\u0000',
+        expected: '\uFFFD\u0000',
+        name: 'unmatched surrogate trail'
+    },
+    {
+        input: '\uDC00\uD800',
+        expected: '\uFFFD\uFFFD',
+        name: 'swapped surrogate pair'
+    },
+    {
+        input: '\uD834\uDD1E',
+        expected: '\uD834\uDD1E',
+        name: 'properly encoded MUSICAL SYMBOL G CLEF (U+1D11E)'
+    }
+];
+
+bad.forEach(function(t) {
+    test(function() {
+        var encoded = new TextEncoder().encode(t.input);
+        var decoded = new TextDecoder().decode(encoded);
+        assert_equals(decoded, t.expected);
+    }, 'USVString handling: ' + t.name);
+});
+
+test(function() {
+    assert_equals(new TextEncoder().encode().length, 0, 'Should default to empty string');
+}, 'USVString default');