Prevent killing UI if heartbeats are pending (#10371) (#10450)

* Prevent killing UI if heartbeats are pending (#10371)

Fixes #9663

* fixed Java 1.8 syntax -> 1.6

1 files changed, 47 insertions, 0 deletions

diff --git a/uitest/src/test/java/com/vaadin/tests/core/LockingUITest.java b/uitest/src/test/java/com/vaadin/tests/core/LockingUITest.java
new file mode 100644
index 0000000000..214adfc94d
--- /dev/null
+++ b/uitest/src/test/java/com/vaadin/tests/core/LockingUITest.java
@@ -0,0 +1,47 @@
+package com.vaadin.tests.core;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import com.vaadin.testbench.elements.ButtonElement;
+import com.vaadin.testbench.elements.NotificationElement;
+import com.vaadin.tests.tb3.SingleBrowserTest;
+
+public class LockingUITest extends SingleBrowserTest {
+
+    @Test
+    public void testLockingTheUIFor4HeartBeats() {
+        openTestURL();
+
+        clickButtonAndCheckNotification("check", LockingUI.ALL_OK);
+        clickButtonAndCheckNotification("lock", LockingUI.LOCKING_ENDED);
+        clickButtonAndCheckNotification("check", LockingUI.ALL_OK);
+    }
+
+    private void clickButtonAndCheckNotification(String buttonId, String text) {
+        checkNoInitialNotification();
+
+        $(ButtonElement.class).id(buttonId).click();
+        testBench().waitForVaadin();
+
+        checkNotification(text);
+    }
+
+    private void checkNotification(String text) {
+        assertTrue("Notification should be displayed",
+                $(NotificationElement.class).exists());
+
+        NotificationElement notification = $(NotificationElement.class).first();
+        assertEquals("Unexpected text content in Notification", text,
+                notification.getText());
+        notification.close();
+    }
+
+    private void checkNoInitialNotification() {
+        assertFalse("Extra notification displayed",
+                $(NotificationElement.class).exists());
+    }
+}