Fix "overflowMode: wrap" TableViews so that the selection checkbox cells have the proper z-index (#2179)

Author: LFDanLu

packages/@react-spectrum/table/test/Table.test.js

@@ -3638,6 +3638,22 @@ describe('TableView', function () {
         act(() => jest.runAllTimers());
         expect(tree.queryByRole('checkbox')).toBeNull();
       });
+
+      it('should return the proper cell z-indexes for overflowMode="wrap"', function () {
+        let tree = renderTable({overflowMode: 'wrap', selectionMode: 'multiple'});
+        let rows = tree.getAllByRole('row');
+        expect(rows).toHaveLength(3);
+
+        for (let row of rows) {
+          for (let [index, cell] of row.childNodes.entries()) {
+            if (index === 0) {
+              expect(cell.style.zIndex).toBe('2');
+            } else {
+              expect(cell.style.zIndex).toBe('1');
+            }
+          }
+        }
+      });
     });
 
     describe('column widths', function () {

packages/@react-stately/virtualizer/src/LayoutInfo.ts

@@ -94,6 +94,7 @@ export class LayoutInfo {
     res.transform = this.transform;
     res.parentKey = this.parentKey;
     res.isSticky = this.isSticky;
+    res.zIndex = this.zIndex;
     return res;
   }
 }

packages/@react-stately/virtualizer/test/LayoutInfo.test.tsx

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 Adobe. All rights reserved.
+ * This file is licensed to you 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 REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import {LayoutInfo, Rect} from '../';
+
+describe('LayoutInfo', () => {
+  it('should return a copy of the current LayoutInfo after calling copy()', () => {
+    let layoutInfo = new LayoutInfo('loader', 'key', new Rect(10, 10, 10, 10));
+    layoutInfo.parentKey = 'parent key';
+    layoutInfo.estimatedSize = true;
+    layoutInfo.isSticky = true;
+    layoutInfo.opacity = 3;
+    layoutInfo.transform = 'scale3d(0.8, 0.8, 0.8)';
+    layoutInfo.zIndex = 5;
+    // Cursory check that layoutInfo has been changed
+    expect(layoutInfo.zIndex).toBe(5);
+
+    let copy = layoutInfo.copy();
+    expect(copy).toEqual(layoutInfo);
+
+  });
+});