Tree widget: Assertion failures when running createTreeWidget tests

[grigasp]

1. Set environment variable NODE_ENV=development
2. Run tree widget tests
3. Notice the failures:

   1) createTreeWidget
        renders supplied trees:
      Error: Assert: Programmer Error
       at assert (node_modules\.pnpm\@[email protected]\node_modules\@itwin\core-bentley\src\Assert.ts:46:9)
       at useTransientState (node_modules\.pnpm\@[email protected]_infkli3j65rh4rjxdkq4hj547y\node_modules\@itwin\appui-react\src\appui-react\widget-panels\useTransientState.tsx:21:9)
       at useTreeWidgetTransientState (src\components\TreeWidgetUiItemsProvider.tsx:100:20)
       at TreeWidgetComponent (src\components\TreeWidgetUiItemsProvider.tsx:73:15)
       at renderWithHooks (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:16141:18)
       at mountIndeterminateComponent (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:20838:13)
       at beginWork (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:22342:16)
       at beginWork$1 (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:27219:14)
       at performUnitOfWork (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:26395:12)
       at workLoopSync (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:26303:5)
       at renderRootSync (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:26271:7)
       at recoverFromConcurrentError (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:25689:20)
       at performConcurrentWorkOnRoot (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:25589:22)
       at flushActQueue (node_modules\.pnpm\[email protected]\node_modules\react\cjs\react.development.js:2662:24)
       at act (node_modules\.pnpm\[email protected]\node_modules\react\cjs\react.development.js:2577:11)
       at E:\itwinjs-1\repos\viewer-components-react\packages\itwin\tree-widget\node_modules\.pnpm\@[email protected][email protected][email protected][email protected]\node_modules\@testing-library\react\dist\act-compat.js:46:25
       at renderRoot (node_modules\.pnpm\@[email protected][email protected][email protected][email protected]\node_modules\@testing-library\react\dist\pure.js:161:26)
       at render (node_modules\.pnpm\@[email protected][email protected][email protected][email protected]\node_modules\@testing-library\react\dist\pure.js:247:10)  
       at customRender (src\test\TestUtils.tsx:204:17)
       at Context.<anonymous> (src\test\TreeWidgetUiItemsProvider.test.tsx:40:11)
   
   2) createTreeWidget
        renders error message if tree component throws:
      Error: Assert: Programmer Error
       at assert (node_modules\.pnpm\@[email protected]\node_modules\@itwin\core-bentley\src\Assert.ts:46:9)
       at useTransientState (node_modules\.pnpm\@[email protected]_infkli3j65rh4rjxdkq4hj547y\node_modules\@itwin\appui-react\src\appui-react\widget-panels\useTransientState.tsx:21:9)
       at useTreeWidgetTransientState (src\components\TreeWidgetUiItemsProvider.tsx:100:20)
       at TreeWidgetComponent (src\components\TreeWidgetUiItemsProvider.tsx:73:15)
       at renderWithHooks (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:16141:18)
       at mountIndeterminateComponent (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:20838:13)
       at beginWork (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:22342:16)
       at beginWork$1 (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:27219:14)
       at performUnitOfWork (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:26395:12)
       at workLoopSync (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:26303:5)
       at renderRootSync (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:26271:7)
       at recoverFromConcurrentError (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:25689:20)
       at performConcurrentWorkOnRoot (node_modules\.pnpm\[email protected][email protected]\node_modules\react-dom\cjs\react-dom.development.js:25589:22)
       at flushActQueue (node_modules\.pnpm\[email protected]\node_modules\react\cjs\react.development.js:2662:24)
       at act (node_modules\.pnpm\[email protected]\node_modules\react\cjs\react.development.js:2577:11)
       at E:\itwinjs-1\repos\viewer-components-react\packages\itwin\tree-widget\node_modules\.pnpm\@[email protected][email protected][email protected][email protected]\node_modules\@testing-library\react\dist\act-compat.js:46:25
       at renderRoot (node_modules\.pnpm\@[email protected][email protected][email protected][email protected]\node_modules\@testing-library\react\dist\pure.js:161:26)
       at render (node_modules\.pnpm\@[email protected][email protected][email protected][email protected]\node_modules\@testing-library\react\dist\pure.js:247:10)  
       at customRender (src\test\TestUtils.tsx:204:17)
       at Context.<anonymous> (src\test\TreeWidgetUiItemsProvider.test.tsx:68:35)

[saskliutas]

There is no simple solution for this. Filled issue in AppUI iTwin/appui#1021