[Refactor] Introduce basic Renderer for completion-style request (#24010)

Signed-off-by: sfeng33 <4florafeng@gmail.com>

tests/entrypoints/test_renderer.py

@@ -0,0 +1,163 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from dataclasses import dataclass
+from typing import Optional
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from vllm.entrypoints.renderer import CompletionRenderer
+
+
+@dataclass
+class MockModelConfig:
+    max_model_len: int = 100
+    encoder_config: Optional[dict] = None
+
+
+class MockTokenizerResult:
+
+    def __init__(self, input_ids):
+        self.input_ids = input_ids
+
+
+@pytest.fixture
+def mock_model_config():
+    return MockModelConfig()
+
+
+@pytest.fixture
+def mock_tokenizer():
+    tokenizer = MagicMock()
+    return tokenizer
+
+
+@pytest.fixture
+def mock_async_tokenizer():
+    async_tokenizer = AsyncMock()
+    return async_tokenizer
+
+
+@pytest.fixture
+def renderer(mock_model_config, mock_tokenizer):
+    return CompletionRenderer(model_config=mock_model_config,
+                              tokenizer=mock_tokenizer,
+                              async_tokenizer_pool={})
+
+
+class TestRenderPrompt:
+    """Test Category A: Basic Functionality Tests"""
+
+    @pytest.mark.asyncio
+    async def test_token_input(self, renderer):
+        tokens = [101, 7592, 2088]
+        results = await renderer.render_prompt(prompt_or_prompts=tokens,
+                                               max_length=100)
+
+        assert len(results) == 1
+        assert results[0]["prompt_token_ids"] == tokens
+
+    @pytest.mark.asyncio
+    async def test_token_list_input(self, renderer):
+        token_lists = [[101, 7592, 2088], [102, 1234, 5678, 9012], [103, 4567]]
+        results = await renderer.render_prompt(prompt_or_prompts=token_lists,
+                                               max_length=100)
+
+        assert len(results) == 3
+        assert results[0]["prompt_token_ids"] == [101, 7592, 2088]
+        assert results[1]["prompt_token_ids"] == [102, 1234, 5678, 9012]
+        assert results[2]["prompt_token_ids"] == [103, 4567]
+
+    @pytest.mark.asyncio
+    async def test_text_input(self, renderer, mock_async_tokenizer):
+        mock_async_tokenizer.return_value = MockTokenizerResult(
+            [101, 7592, 2088])
+        renderer.async_tokenizer_pool[
+            renderer.tokenizer] = mock_async_tokenizer
+
+        results = await renderer.render_prompt(prompt_or_prompts="Hello world",
+                                               max_length=100)
+
+        assert len(results) == 1
+        assert results[0]["prompt_token_ids"] == [101, 7592, 2088]
+        mock_async_tokenizer.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_text_list_input(self, renderer, mock_async_tokenizer):
+        mock_async_tokenizer.return_value = MockTokenizerResult(
+            [101, 7592, 2088])
+        renderer.async_tokenizer_pool[
+            renderer.tokenizer] = mock_async_tokenizer
+
+        text_list_input = ["Hello world", "How are you?", "Good morning"]
+        results = await renderer.render_prompt(
+            prompt_or_prompts=text_list_input, max_length=100)
+
+        assert len(results) == 3
+        for result in results:
+            assert result["prompt_token_ids"] == [101, 7592, 2088]
+        assert mock_async_tokenizer.call_count == 3
+
+    @pytest.mark.asyncio
+    async def test_no_truncation(self, renderer, mock_async_tokenizer):
+        mock_async_tokenizer.return_value = MockTokenizerResult(
+            [101, 7592, 2088])
+        renderer.async_tokenizer_pool[
+            renderer.tokenizer] = mock_async_tokenizer
+
+        results = await renderer.render_prompt(prompt_or_prompts="Hello world",
+                                               max_length=100)
+
+        assert len(results) == 1
+        call_args = mock_async_tokenizer.call_args
+        assert "truncation" not in call_args.kwargs or call_args.kwargs[
+            "truncation"] is False
+
+    @pytest.mark.asyncio
+    async def test_truncation_positive(self, renderer, mock_async_tokenizer):
+        mock_async_tokenizer.return_value = MockTokenizerResult(
+            [101, 7592, 2088])  # Truncated
+        renderer.async_tokenizer_pool[
+            renderer.tokenizer] = mock_async_tokenizer
+
+        results = await renderer.render_prompt(prompt_or_prompts="Hello world",
+                                               max_length=100,
+                                               truncate_prompt_tokens=50)
+
+        assert len(results) == 1
+        call_args = mock_async_tokenizer.call_args
+        assert call_args.kwargs["truncation"] is True
+        assert call_args.kwargs["max_length"] == 50
+
+    @pytest.mark.asyncio
+    async def test_token_truncation_last_elements(self, renderer):
+        # Test that token truncation keeps the last N elements
+        long_tokens = [100, 101, 102, 103, 104, 105, 106, 107, 108,
+                       109]  # 10 tokens
+        results = await renderer.render_prompt(prompt_or_prompts=long_tokens,
+                                               max_length=100,
+                                               truncate_prompt_tokens=5)
+
+        assert len(results) == 1
+        # Should keep the last 5 tokens: [105, 106, 107, 108, 109]
+        assert results[0]["prompt_token_ids"] == [105, 106, 107, 108, 109]
+
+    @pytest.mark.asyncio
+    async def test_max_length_exceeded(self, renderer):
+        long_tokens = list(range(150))  # Exceeds max_model_len=100
+
+        with pytest.raises(ValueError, match="maximum context length"):
+            await renderer.render_prompt(prompt_or_prompts=long_tokens,
+                                         max_length=100)
+
+    @pytest.mark.asyncio
+    async def test_no_tokenizer_for_text(self, mock_model_config):
+        renderer_no_tokenizer = CompletionRenderer(
+            model_config=mock_model_config,
+            tokenizer=None,
+            async_tokenizer_pool={})
+
+        with pytest.raises(ValueError, match="No tokenizer available"):
+            await renderer_no_tokenizer.render_prompt(
+                prompt_or_prompts="Hello world", max_length=100)