[ZEPPELIN-6409] Wait for Angular paragraph output refresh via stalenessOf

The Angular paragraph re-run replaces the output DOM element. Without
waiting for the old element to become stale, the test may see the old
FINISHED state and try to find the new output before it exists.

Fix: capture the old output element before re-run, wait for stalenessOf
to confirm DOM refresh, then wait for the new element to appear.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jongyoul

zeppelin-integration/src/test/java/org/apache/zeppelin/integration/ZeppelinIT.java

@@ -33,12 +33,15 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import java.time.Duration;
 import org.openqa.selenium.By;
+import org.openqa.selenium.JavascriptExecutor;
 import org.openqa.selenium.Keys;
 import org.openqa.selenium.StaleElementReferenceException;
 import org.openqa.selenium.TimeoutException;
-import org.openqa.selenium.JavascriptExecutor;
 import org.openqa.selenium.WebElement;
+import org.openqa.selenium.support.ui.ExpectedConditions;
+import org.openqa.selenium.support.ui.WebDriverWait;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -327,22 +330,30 @@ void testAngularRunParagraph() throws Exception {
               "%angular <div id=\\'angularRunParagraph\\' ng-click=\\'z.runParagraph(\""
                       + secondParagraphId.trim()
                       + "\")\\'>Run second paragraph</div>");
+
+      // Capture old output element before re-run to detect when it gets replaced
+      WebElement oldAngularDiv = manager.getWebDriver().findElement(By.xpath(
+              getParagraphXPath(1) + "//div[@id=\"angularRunParagraph\"]"));
+
       runParagraph(1);
+
+      // Wait for the old output element to become stale (proves the paragraph output
+      // was actually refreshed, avoiding race where waitForParagraph sees the old FINISHED state)
+      new WebDriverWait(manager.getWebDriver(), Duration.ofSeconds(MAX_BROWSER_TIMEOUT_SEC))
+              .until(ExpectedConditions.stalenessOf(oldAngularDiv));
+
       waitForParagraph(1, "FINISHED");
 
-      // Wait for Angular to re-render the output with ng-click binding
-      waitForText("Run second paragraph", By.xpath(
-              getParagraphXPath(1) + "//div[@id=\"angularRunParagraph\"]"));
+      // Wait for new Angular output to render
+      WebElement newAngularDiv = visibilityWait(By.xpath(
+              getParagraphXPath(1) + "//div[@id=\"angularRunParagraph\"]"), MAX_BROWSER_TIMEOUT_SEC);
 
       // Set new text value for 2nd paragraph
       setTextOfParagraph(2, "%sh echo NEW_VALUE");
 
       // Click on Angular-rendered div to trigger z.runParagraph() function.
-      // Use JavaScript click because Angular-compiled ng-click elements may not be
-      // considered "clickable" by Selenium's native click (overlay/stale issues).
-      WebElement angularDiv = visibilityWait(By.xpath(
-              getParagraphXPath(1) + "//div[@id=\"angularRunParagraph\"]"), MAX_BROWSER_TIMEOUT_SEC);
-      ((JavascriptExecutor) manager.getWebDriver()).executeScript("arguments[0].click();", angularDiv);
+      // Use JavaScript click to bypass overlay/clickability issues with ng-click elements.
+      ((JavascriptExecutor) manager.getWebDriver()).executeScript("arguments[0].click();", newAngularDiv);
       ZeppelinITUtils.sleep(1000, false);
 
       waitForParagraph(2, "FINISHED");