Restore accidentally removed test_retrieve_via_agent_with_enable_metadata

- The test was accidentally removed during the previous commit
- Restored the complete test function with both enabled and disabled metadata scenarios
- Test passes successfully

Author: Tirthanu Ghosh

tests/test_retrieve.py

@@ -796,3 +796,26 @@ def test_retrieve_via_agent_with_override_search_type(agent, mock_boto3_client):
         knowledgeBaseId="test-kb-id",
         retrievalConfiguration={"vectorSearchConfiguration": {"numberOfResults": 10, "overrideSearchType": "HYBRID"}},
     )
+
+
+def test_retrieve_via_agent_with_enable_metadata(agent, mock_boto3_client):
+    """Test retrieving via the agent interface with enableMetadata."""
+    with mock.patch.dict(os.environ, {"KNOWLEDGE_BASE_ID": "agent-kb-id"}):
+        # Test with metadata enabled
+        result = agent.tool.retrieve(text="agent query", knowledgeBaseId="test-kb-id", enableMetadata=True)
+
+    result_text = extract_result_text(result)
+    assert "Retrieved" in result_text
+    assert "results with score >=" in result_text
+    assert "Metadata:" in result_text
+    assert "test-source" in result_text
+
+    # Test with metadata disabled
+    with mock.patch.dict(os.environ, {"KNOWLEDGE_BASE_ID": "agent-kb-id"}):
+        result = agent.tool.retrieve(text="agent query", knowledgeBaseId="test-kb-id", enableMetadata=False)
+
+    result_text = extract_result_text(result)
+    assert "Retrieved" in result_text
+    assert "results with score >=" in result_text
+    assert "Metadata:" not in result_text
+    assert "test-source" not in result_text