fix(Truncate): remove resize observer

packages/react-core/src/components/ClipboardCopy/__tests__/ClipboardCopyTruncateIntegration.test.tsx

@@ -0,0 +1,32 @@
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { ClipboardCopy, ClipboardCopyVariant } from '../ClipboardCopy';
+
+// This test file uses the real Truncate component for integration testing, instead of a mock
+
+test('Tooltip appears on keyboard focus when using inline-compact variant with truncation', async () => {
+  const user = userEvent.setup();
+  const longText = 'This is a very long piece of content that should be truncated when the container is too small';
+
+  render(
+    <ClipboardCopy
+      variant={ClipboardCopyVariant.inlineCompact}
+      truncation={{ maxCharsDisplayed: 20 }}
+      data-testid="clipboard-copy"
+    >
+      {longText}
+    </ClipboardCopy>
+  );
+
+  expect(screen.queryByText(longText)).not.toBeInTheDocument();
+  expect(screen.queryByRole('tooltip')).not.toBeInTheDocument();
+
+  await user.tab();
+
+  const clipboardCopy = screen.getByTestId('clipboard-copy');
+  expect(clipboardCopy).toHaveFocus();
+
+  const tooltip = screen.getByRole('tooltip');
+  expect(tooltip).toBeInTheDocument();
+  expect(tooltip).toHaveTextContent(longText);
+});

packages/react-core/src/components/Truncate/Truncate.tsx

@@ -4,6 +4,7 @@ import { css } from '@patternfly/react-styles';
 import { Tooltip, TooltipPosition, TooltipProps } from '../Tooltip';
 import { getReferenceElement } from '../../helpers';
 import { getResizeObserver } from '../../helpers/resizeObserver';
+import { debounce } from '../../helpers/util';
 
 export enum TruncatePosition {
   start = 'start',
@@ -130,12 +131,12 @@ const TruncateBase: React.FunctionComponent<TruncateProps> = ({
       const totalTextWidth = calculateTotalTextWidth(textElement, trailingNumChars, content);
       const textWidth = position === 'middle' ? totalTextWidth : textElement.scrollWidth;
 
-      const handleResize = () => {
+      const debouncedHandleResize = debounce(() => {
         const parentWidth = getActualWidth(parentElement);
         setIsTruncated(textWidth >= parentWidth);
-      };
+      }, 500);
 
-      const observer = getResizeObserver(parentElement, handleResize);
+      const observer = getResizeObserver(parentElement, debouncedHandleResize);
 
       return () => {
         observer();
@@ -147,7 +148,7 @@ const TruncateBase: React.FunctionComponent<TruncateProps> = ({
     if (shouldRenderByMaxChars) {
       setIsTruncated(content.length > maxCharsDisplayed);
     }
-  }, [shouldRenderByMaxChars]);
+  }, [shouldRenderByMaxChars, content.length, maxCharsDisplayed]);
 
   useEffect(() => {
     setShouldRenderByMaxChars(maxCharsDisplayed > 0);

packages/react-core/src/components/Truncate/__tests__/Truncate.test.tsx

@@ -1,12 +1,12 @@
-import { render, screen, within } from '@testing-library/react';
-import { Truncate, TruncatePosition } from '../Truncate';
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { Truncate } from '../Truncate';
 import styles from '@patternfly/react-styles/css/components/Truncate/truncate';
 import '@testing-library/jest-dom';
 
 jest.mock('../../Tooltip', () => ({
   Tooltip: ({ content, position, children, triggerRef, ...props }) => (
     <div data-testid="Tooltip-mock" {...props}>
-      <div data-testid="Tooltip-mock-content-container">Test {content}</div>
+      <div>Test {content}</div>
       <p>{`position: ${position}`}</p>
       {children}
     </div>
@@ -242,3 +242,21 @@ describe('Truncation with maxCharsDisplayed', () => {
     expect(asFragment()).toMatchSnapshot();
   });
 });
+
+test('Tooltip appears on keyboard focus when external triggerRef is provided (ClipboardCopy regression test)', () => {
+  const mockTriggerRef = { current: document.createElement('div') };
+
+  render(
+    <Truncate
+      content="This is a very long piece of content that should be truncated when the container is too small"
+      tooltipProps={{ triggerRef: mockTriggerRef }}
+    />
+  );
+
+  // Simulate keyboard focus on the external trigger element
+  fireEvent.focus(mockTriggerRef.current);
+
+  // The tooltip should be present and visible
+  const tooltip = screen.getByTestId('Tooltip-mock');
+  expect(tooltip).toBeInTheDocument();
+});

packages/react-core/src/components/Truncate/__tests__/__snapshots__/Truncate.test.tsx.snap

@@ -5,9 +5,7 @@ exports[`Truncation with maxCharsDisplayed Matches snapshot with default positio
   <div
     data-testid="Tooltip-mock"
   >
-    <div
-      data-testid="Tooltip-mock-content-container"
-    >
+    <div>
       Test Test truncation content
     </div>
     <p>
@@ -43,9 +41,7 @@ exports[`renders default truncation 1`] = `
   <div
     data-testid="Tooltip-mock"
   >
-    <div
-      data-testid="Tooltip-mock-content-container"
-    >
+    <div>
       Test Vestibulum interdum risus et enim faucibus, sit amet molestie est accumsan.
     </div>
     <p>
@@ -70,9 +66,7 @@ exports[`renders start truncation with &lrm; at start and end 1`] = `
   <div
     data-testid="Tooltip-mock"
   >
-    <div
-      data-testid="Tooltip-mock-content-container"
-    >
+    <div>
       Test Vestibulum interdum risus et enim faucibus, sit amet molestie est accumsan.
     </div>
     <p>