fix unit test

Signed-off-by: Ruirui Zhang <mariazrr@amazon.com>

plugins/workload-management/src/test/java/org/opensearch/plugin/wlm/service/QueryGroupPersistenceServiceTests.java

@@ -112,7 +112,7 @@ public void testCreateQueryGroupOverflowAllocation() {
 
     /**
      * Test case to ensure the error is thrown when we already have the max allowed number of QueryGroups, but
-     * we try to create another one
+     * we want to create another one
      */
     public void testCreateQueryGroupOverflowCount() {
         QueryGroup toCreate = builder().name(NAME_NONE_EXISTED)
@@ -133,4 +133,16 @@ public void testCreateQueryGroupOverflowCount() {
         );
         assertThrows(RuntimeException.class, () -> queryGroupPersistenceService1.saveQueryGroupInClusterState(toCreate, clusterState));
     }
+
+    public void testInvalidMaxQueryGroupCount() {
+        Settings settings = Settings.builder().put(QUERY_GROUP_COUNT_SETTING_NAME, 2).build();
+        ClusterSettings clusterSettings = new ClusterSettings(settings, clusterSettingsSet());
+        ClusterService clusterService = new ClusterService(settings, clusterSettings, mock(ThreadPool.class));
+        QueryGroupPersistenceService queryGroupPersistenceService = new QueryGroupPersistenceService(
+            clusterService,
+            settings,
+            clusterSettings
+        );
+        assertThrows(IllegalArgumentException.class, () -> queryGroupPersistenceService.setMaxQueryGroupCount(-1));
+    }
 }

server/src/test/java/org/opensearch/cluster/metadata/QueryGroupMetadataTests.java

@@ -44,7 +44,7 @@ public void testToXContent() throws IOException {
         queryGroupMetadata.toXContent(builder, null);
         builder.endObject();
         assertEquals(
-            "{\"ajakgakg983r92_4242\":{\"_id\":\"ajakgakg983r92_4242\",\"name\":\"test\",\"resiliency_mode\":\"enforced\",\"updatedAt\":1720047207,\"resourceLimits\":{\"memory\":0.5}}}",
+            "{\"ajakgakg983r92_4242\":{\"_id\":\"ajakgakg983r92_4242\",\"name\":\"test\",\"resiliency_mode\":\"enforced\",\"updated_at\":1720047207,\"resource_limits\":{\"memory\":0.5}}}",
             builder.toString()
         );
     }