fix(tests): make WYSIWYG tests more robust and deterministic by initializing and attaching elements consistently, awaiting customElements/firstUpdated, adjusting selectors and assertions, and cleaning up DOM after tests

test/test.shadow-dom-containment.browser.ts

@@ -4,19 +4,20 @@ import { WysiwygSelection } from '../ts_web/elements/00group-input/dees-input-wy
 
 tap.test('Shadow DOM containment should work correctly', async () => {
   console.log('=== Testing Shadow DOM Containment ===');
-  
-  // Create a WYSIWYG block component
-  const block = await webhelpers.fixture<DeesWysiwygBlock>(
-    '<dees-wysiwyg-block></dees-wysiwyg-block>'
-  );
-  
-  // Set the block data
+
+  // Wait for custom element to be defined
+  await customElements.whenDefined('dees-wysiwyg-block');
+
+  // Create a WYSIWYG block component - set properties BEFORE attaching to DOM
+  const block = document.createElement('dees-wysiwyg-block') as DeesWysiwygBlock;
+
+  // Set the block data before attaching to DOM so firstUpdated() sees them
   block.block = {
     id: 'test-1',
     type: 'paragraph',
     content: 'Hello world test content'
   };
-  
+
   block.handlers = {
     onInput: () => {},
     onKeyDown: () => {},
@@ -25,8 +26,12 @@ tap.test('Shadow DOM containment should work correctly', async () => {
     onCompositionStart: () => {},
     onCompositionEnd: () => {}
   };
-  
+
+  // Now attach to DOM and wait for render
+  document.body.appendChild(block);
   await block.updateComplete;
+  // Wait for firstUpdated to populate the container
+  await new Promise(resolve => setTimeout(resolve, 50));
   
   // Get the paragraph element inside Shadow DOM
   const container = block.shadowRoot?.querySelector('.wysiwyg-block-container') as HTMLElement;
@@ -93,6 +98,9 @@ tap.test('Shadow DOM containment should work correctly', async () => {
       expect(splitResult.after).toEqual(' test content');
     }
   }
+
+  // Clean up
+  document.body.removeChild(block);
 });
 
 tap.test('Shadow DOM containment across different shadow roots', async () => {