diff --git a/packages/util/__tests__/lib/element.test.ts b/packages/util/__tests__/lib/element.test.ts
index 00de7bc1..9392033c 100644
--- a/packages/util/__tests__/lib/element.test.ts
+++ b/packages/util/__tests__/lib/element.test.ts
@@ -1,4 +1,4 @@
-import { createUUID, deepClone, getElementPositionFromList } from '@idraw/util';
+import { createUUID, getElementPositionFromList } from '@idraw/util';
 import type { Elements } from '@idraw/types';
 const getElemBase = () => {
   return {
diff --git a/packages/util/__tests__/lib/group.test.ts b/packages/util/__tests__/lib/group.test.ts
new file mode 100644
index 00000000..5cbf385d
--- /dev/null
+++ b/packages/util/__tests__/lib/group.test.ts
@@ -0,0 +1,92 @@
+import type { Element } from '@idraw/types';
+import { groupElementsByPosition, ungroupElementsByPosition, insertElementToListByPosition } from '@idraw/util';
+
+const createList = () => {
+  const list: Element[] = [
+    { uuid: '0', type: 'rect', x: 20, y: 20, w: 50, h: 50, detail: {} },
+    { uuid: '1', type: 'rect', x: 40, y: 40, w: 50, h: 50, detail: {} },
+    { uuid: '2', type: 'rect', x: 60, y: 60, w: 50, h: 50, detail: {} },
+    { uuid: '3', type: 'rect', x: 80, y: 80, w: 50, h: 50, detail: {} },
+    { uuid: '4', type: 'rect', x: 100, y: 100, w: 50, h: 50, detail: {} }
+  ];
+  return list;
+};
+
+const createGroupedList = () => {
+  const list: Element[] = [
+    { uuid: '0', type: 'rect', x: 20, y: 20, w: 50, h: 50, detail: {} },
+    {
+      name: 'Group',
+      uuid: 'group-id',
+      type: 'group',
+      x: 40,
+      y: 40,
+      w: 90,
+      h: 90,
+      detail: {
+        children: [
+          { uuid: '1', type: 'rect', x: 0, y: 0, w: 50, h: 50, detail: {} },
+          { uuid: '2', type: 'rect', x: 20, y: 20, w: 50, h: 50, detail: {} },
+          { uuid: '3', type: 'rect', x: 40, y: 40, w: 50, h: 50, detail: {} }
+        ]
+      }
+    },
+    { uuid: '4', type: 'rect', x: 100, y: 100, w: 50, h: 50, detail: {} }
+  ];
+  return list;
+};
+
+describe('@idraw/util: group ', () => {
+  test('groupElementsByPosition', () => {
+    const list = createList();
+    groupElementsByPosition(list, [[1], [2], [3]]);
+    list[1].uuid = 'group-id';
+    expect(list).toStrictEqual(createGroupedList());
+  });
+
+  test('groupElementsByPosition with disordered positions', () => {
+    const list = createList();
+    groupElementsByPosition(list, [[3], [1], [2]]);
+    list[1].uuid = 'group-id';
+    expect(list).toStrictEqual(createGroupedList());
+  });
+
+  test('groupElementsByPosition with deep position', () => {
+    const list = createList();
+    list[0].type = 'group';
+    list[0].detail = { children: createList() };
+    groupElementsByPosition(list, [
+      [0, 1],
+      [0, 2],
+      [0, 3]
+    ]);
+    list[0].detail.children[1].uuid = 'group-id';
+
+    const expectedList = createList();
+    expectedList[0].type = 'group';
+    expectedList[0].detail = { children: createGroupedList() };
+    expect(list).toStrictEqual(expectedList);
+  });
+
+  test('groupElementsByPosition with deep position and disordered positions', () => {
+    const list = createList();
+    list[0].type = 'group';
+    list[0].detail = { children: createList() };
+    groupElementsByPosition(list, [
+      [0, 3],
+      [0, 1],
+      [0, 2]
+    ]);
+    list[0].detail.children[1].uuid = 'group-id';
+    const expectedList = createList();
+    expectedList[0].type = 'group';
+    expectedList[0].detail = { children: createGroupedList() };
+    expect(list).toStrictEqual(expectedList);
+  });
+
+  test('upgroupElementsByPosition', () => {
+    const list = createGroupedList();
+    ungroupElementsByPosition(list, [1]);
+    expect(list).toStrictEqual(createList());
+  });
+});
diff --git a/packages/util/__tests__/lib/rotate.test.ts b/packages/util/__tests__/lib/rotate.test.ts
index d25a5e31..014d862e 100644
--- a/packages/util/__tests__/lib/rotate.test.ts
+++ b/packages/util/__tests__/lib/rotate.test.ts
@@ -1,4 +1,4 @@
-import { rotatePoint, parseAngleToRadian } from '@idraw/util';
+import { rotatePoint, parseAngleToRadian, parseRadianToAngle, calcRadian } from '@idraw/util';
 
 describe('@idraw/util: rotate', () => {
   test('rotatePoint', () => {
@@ -211,4 +211,17 @@ describe('@idraw/util: rotate', () => {
     expect(start4.x).toBeCloseTo(start0.x);
     expect(start4.y).toBeCloseTo(start0.y);
   });
+
+  test('calcRadian 1', () => {
+    const start = { x: 402, y: 328 };
+    const end = { x: 341, y: 414 };
+    const center = { x: 400, y: 400 };
+    expect(parseRadianToAngle(calcRadian(center, start, end))).toBeCloseTo(255.060132615518);
+  });
+  test('calcRadian 2', () => {
+    const start = { x: 402, y: 328 };
+    const end = { x: 340, y: 392 };
+    const center = { x: 400, y: 400 };
+    expect(parseRadianToAngle(calcRadian(center, start, end))).toBeCloseTo(276.00350309739684);
+  });
 });