Add unit test case for StandaloneHaServices constructor

Author: lurongjiang

flink-runtime/src/test/java/org/apache/flink/runtime/highavailability/nonha/standalone/StandaloneHaServicesTest.java

@@ -30,6 +30,8 @@
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -141,4 +143,28 @@ public void testJobMasterLeaderRetrieval() throws Exception {
                 .notifyLeaderAddress(
                         eq(jobManagerAddress2), eq(HighAvailabilityServices.DEFAULT_LEADER_ID));
     }
+
+    /**
+     * Tests that the constructor properly validates null parameters and provides meaningful error messages.
+     */
+    @Test
+    public void testConstructorNullValidation() {
+        // Test null resourceManagerAddress
+        Exception exception = assertThrows(
+                NullPointerException.class,
+                () -> new StandaloneHaServices(null, dispatcherAddress, webMonitorAddress));
+        assertTrue(exception.getMessage().contains("resourceManagerAddress"));
+
+        // Test null dispatcherAddress
+        exception = assertThrows(
+                NullPointerException.class,
+                () -> new StandaloneHaServices(resourceManagerAddress, null, webMonitorAddress));
+        assertTrue(exception.getMessage().contains("dispatcherAddress"));
+
+        // Test null clusterRestEndpointAddress
+        exception = assertThrows(
+                NullPointerException.class,
+                () -> new StandaloneHaServices(resourceManagerAddress, dispatcherAddress, null));
+        assertTrue(exception.getMessage().contains("clusterRestEndpointAddress"));
+    }
 }