Test \b escape inside CharacterClass in Unicode RegExp

test/built-ins/RegExp/unicode_character_class_backspace_escape.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: prod-ClassEscapes
+description: >
+  \b escape inside CharacterClass is valid in Unicode patterns (unlike \B).
+info: |
+  ClassEscape[U] ::
+    b
+
+  Static Semantics: CharacterValue
+
+  ClassEscape :: b
+
+  1. Return the code point value of U+0008 (BACKSPACE).
+---*/
+
+assert(/[\b]/u.test('\b'));
+assert(/[\b-A]/u.test('A'));