Add unit test

test/components/builders/test_chat_prompt_builder.py

@@ -5,7 +5,7 @@
 from haystack.components.builders.chat_prompt_builder import ChatPromptBuilder
 from haystack import component
 from haystack.core.pipeline.pipeline import Pipeline
-from haystack.dataclasses.chat_message import ChatMessage
+from haystack.dataclasses.chat_message import ChatMessage, ChatRole
 from haystack.dataclasses.document import Document
 
 
@@ -194,6 +194,17 @@ def test_run_overwriting_default_template_with_variables(self):
 
         assert builder.run(template, name="John", var1="Big") == expected_result
 
+    def test_run_with_meta(self):
+        """
+        Test that the ChatPromptBuilder correctly handles meta data.
+        It should render the message and copy the meta data from the original message.
+        """
+        m = ChatMessage(content="This is a {{ variable }}", role=ChatRole.USER, name=None, meta={"test": "test"})
+        builder = ChatPromptBuilder(template=[m])
+        res = builder.run(variable="test")
+        res_msg = ChatMessage(content="This is a test", role=ChatRole.USER, name=None, meta={"test": "test"})
+        assert res == {"prompt": [res_msg]}
+
     def test_run_with_invalid_template(self):
         builder = ChatPromptBuilder()