add UT for null action input

Signed-off-by: Jing Zhang <[email protected]>

ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/AgentUtilsTest.java

@@ -612,6 +612,18 @@ public void testConstructToolParams() {
         });
     }
 
+    @Test
+    public void testConstructToolParamsNullActionInput() {
+        String question = "dummy question";
+        String actionInput = null;
+        verifyConstructToolParams(question, actionInput, (toolParams) -> {
+            Assert.assertEquals(3, toolParams.size());
+            Assert.assertEquals("value1", toolParams.get("key1"));
+            Assert.assertNull(toolParams.get("llm_generated_action_input"));
+            Assert.assertNull(toolParams.get("input"));
+        });
+    }
+
     @Test
     public void testConstructToolParams_UseOriginalInput() {
         String question = "dummy question";