feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

frontend/packages/common/chat-area/text-grab/__tests__/get-range-direction.test.ts

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+ 
+import { getRangeDirection } from '../src/utils/helper/get-range-direction';
+
+describe('getRangeDirection', () => {
+  it('should return "none" when the range start and end are the same', () => {
+    const range = document.createRange();
+    const div = document.createElement('div');
+    document.body.appendChild(div); // 确保节点在 DOM 中
+    range.setStart(div, 0);
+    range.setEnd(div, 0);
+
+    const direction = getRangeDirection(range);
+    expect(direction).toBe('none');
+  });
+
+  it('should return "forward" when the range is selected forwards', () => {
+    const div = document.createElement('div');
+    document.body.appendChild(div); // 确保节点在 DOM 中
+    div.textContent = 'Test content';
+    const range = document.createRange();
+    range.setStart(div.firstChild as Node, 0);
+    range.setEnd(div.firstChild as Node, 4); // 选择了 "Test"
+
+    const direction = getRangeDirection(range);
+    expect(direction).toBe('forward');
+  });
+});