Add chat format test.

Author: abetlen

llama_cpp/llama_chat_format.py

@@ -878,19 +878,21 @@ def format_chatml(
 
 
 @register_chat_format("mistral-instruct")
-def format_mistral(
+def format_mistral_instruct(
     messages: List[llama_types.ChatCompletionRequestMessage],
     **kwargs: Any,
 ) -> ChatFormatterResponse:
-    _roles = dict(user="[INST] ", assistant="[/INST]")
-    _sep = " "
-    system_template = """<s>{system_message}"""
-    system_message = _get_system_message(messages)
-    system_message = system_template.format(system_message=system_message)
-    _messages = _map_roles(messages, _roles)
-    _messages.append((_roles["assistant"], None))
-    _prompt = _format_no_colon_single(system_message, _messages, _sep)
-    return ChatFormatterResponse(prompt=_prompt)
+    bos = "<s>"
+    eos = "</s>"
+    stop = eos
+    prompt = bos
+    for message in messages:
+        if message["role"] == "user" and message["content"] is not None and isinstance(message["content"], str):
+            prompt += "[INST] " + message["content"]
+        elif message["role"] == "assistant" and message["content"] is not None and isinstance(message["content"], str):
+            prompt += " [/INST]" + message["content"] + eos
+    prompt += " [/INST]"
+    return ChatFormatterResponse(prompt=prompt, stop=stop)
 
 
 @register_chat_format("chatglm3")

tests/test_llama_chat_format.py

@@ -1,10 +1,33 @@
 import json
 
+import jinja2
+
 from llama_cpp import (
     ChatCompletionRequestUserMessage,
 )
+import llama_cpp.llama_types as llama_types
+import llama_cpp.llama_chat_format as llama_chat_format
+
 from llama_cpp.llama_chat_format import hf_tokenizer_config_to_chat_formatter
 
+def test_mistral_instruct():
+    chat_template = "{{ bos_token }}{% for message in messages %}{% if (message['role'] == 'user') != (loop.index0 % 2 == 0) %}{{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}{% endif %}{% if message['role'] == 'user' %}{{ '[INST] ' + message['content'] + ' [/INST]' }}{% elif message['role'] == 'assistant' %}{{ message['content'] + eos_token}}{% else %}{{ raise_exception('Only user and assistant roles are supported!') }}{% endif %}{% endfor %}"
+    chat_formatter = jinja2.Template(chat_template)
+    messages = [
+        llama_types.ChatCompletionRequestUserMessage(role="user", content="Instruction"),
+        llama_types.ChatCompletionRequestAssistantMessage(role="assistant", content="Model answer"),
+        llama_types.ChatCompletionRequestUserMessage(role="user", content="Follow-up instruction"),
+    ]
+    response = llama_chat_format.format_mistral_instruct(
+        messages=messages,
+    )
+    reference = chat_formatter.render(
+        messages=messages,
+        bos_token="<s>",
+        eos_token="</s>",
+    )
+    assert response.prompt == reference
+
 
 mistral_7b_tokenizer_config = """{
   "add_bos_token": true,