import unittest
import subprocess
import time
import backend_pb2
import backend_pb2_grpc

import grpc

import unittest
import subprocess
import time
import grpc
import backend_pb2_grpc
import backend_pb2

class TestBackendServicer(unittest.TestCase):
    """
    TestBackendServicer is the class that tests the gRPC service.

    This class contains methods to test the startup and shutdown of the gRPC service.
    """
    def setUp(self):
        self.service = subprocess.Popen(["python", "backend.py", "--addr", "localhost:50051"])
        time.sleep(10)

    def tearDown(self) -> None:
        self.service.terminate()
        self.service.wait()

    def test_server_startup(self):
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.Health(backend_pb2.HealthMessage())
                self.assertEqual(response.message, b'OK')
        except Exception as err:
            print(err)
            self.fail("Server failed to start")
        finally:
            self.tearDown()
    def test_load_model(self):
        """
        This method tests if the model is loaded successfully
        """
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.LoadModel(backend_pb2.ModelOptions(Model="facebook/opt-125m"))
                self.assertTrue(response.success)
                self.assertEqual(response.message, "Model loaded successfully")
        except Exception as err:
            print(err)
            self.fail("LoadModel service failed")
        finally:
            self.tearDown()

    def test_text(self):
        """
        This method tests if the embeddings are generated successfully
        """
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.LoadModel(backend_pb2.ModelOptions(Model="facebook/opt-125m"))
                self.assertTrue(response.success)
                req = backend_pb2.PredictOptions(Prompt="The capital of France is")
                resp = stub.Predict(req)
                self.assertIsNotNone(resp.message)
        except Exception as err:
            print(err)
            self.fail("text service failed")
        finally:
            self.tearDown()

    def test_sampling_params(self):
        """
        This method tests if all sampling parameters are correctly processed
        NOTE: this does NOT test for correctness, just that we received a compatible response
        """
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.LoadModel(backend_pb2.ModelOptions(Model="facebook/opt-125m"))
                self.assertTrue(response.success)

                req = backend_pb2.PredictOptions(
                    Prompt="The capital of France is",
                    TopP=0.8,
                    Tokens=50,
                    Temperature=0.7,
                    TopK=40,
                    PresencePenalty=0.1,
                    FrequencyPenalty=0.2,
                    RepetitionPenalty=1.1,
                    MinP=0.05,
                    Seed=42,
                    StopPrompts=["\n"],
                    StopTokenIds=[50256],
                    BadWords=["badword"],
                    IncludeStopStrInOutput=True,
                    IgnoreEOS=True,
                    MinTokens=5,
                    Logprobs=5,
                    PromptLogprobs=5,
                    SkipSpecialTokens=True,
                    SpacesBetweenSpecialTokens=True,
                    TruncatePromptTokens=10,
                    GuidedDecoding=True,
                    N=2,
                )
                resp = stub.Predict(req)
                self.assertIsNotNone(resp.message)
                self.assertIsNotNone(resp.logprobs)
        except Exception as err:
            print(err)
            self.fail("sampling params service failed")
        finally:
            self.tearDown()

    def test_explicit_zero_temperature_and_seed_are_preserved(self):
        """Temperature=0 is greedy decoding and 0 is a valid seed — neither is
        an unset value. A dropped seed turns a reproducible request random."""
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer

        servicer = BackendServicer()
        request = backend_pb2.PredictOptions(Prompt="hello", Temperature=0, Seed=0)
        sampling_params = servicer._build_sampling_params(request)
        self.assertEqual(sampling_params.temperature, 0)
        self.assertEqual(sampling_params.seed, 0)
        # Other protobuf-default scalar fields must remain filtered.
        self.assertEqual(sampling_params.top_p, 0.9)


    def test_messages_to_dicts(self):
        """
        Tests _messages_to_dicts conversion of proto Messages to dicts.
        """
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        servicer = BackendServicer()
        msgs = [
            backend_pb2.Message(role="user", content="hello"),
            backend_pb2.Message(
                role="assistant",
                content="",
                tool_calls='[{"id":"call_1","type":"function","function":{"name":"foo","arguments":"{}"}}]',
                reasoning_content="thinking...",
            ),
            backend_pb2.Message(role="tool", content="result", name="foo", tool_call_id="call_1"),
        ]
        result = servicer._messages_to_dicts(msgs)
        self.assertEqual(len(result), 3)
        self.assertEqual(result[0], {"role": "user", "content": "hello"})
        self.assertEqual(result[1]["reasoning_content"], "thinking...")
        self.assertIsInstance(result[1]["tool_calls"], list)
        self.assertEqual(result[1]["tool_calls"][0]["id"], "call_1")
        self.assertEqual(result[2]["tool_call_id"], "call_1")
        self.assertEqual(result[2]["name"], "foo")

    def test_parse_options(self):
        """
        Tests _parse_options correctly parses key:value strings.
        """
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        servicer = BackendServicer()
        opts = servicer._parse_options([
            "tool_parser:hermes",
            "reasoning_parser:deepseek_r1",
            "invalid_no_colon",
            "key_with_colons:a:b:c",
        ])
        self.assertEqual(opts["tool_parser"], "hermes")
        self.assertEqual(opts["reasoning_parser"], "deepseek_r1")
        self.assertEqual(opts["key_with_colons"], "a:b:c")
        self.assertNotIn("invalid_no_colon", opts)

    def test_apply_engine_args_known_keys(self):
        """
        Tests _apply_engine_args overlays user-supplied JSON onto AsyncEngineArgs.
        """
        import sys, os, json as _json
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        from vllm.engine.arg_utils import AsyncEngineArgs

        servicer = BackendServicer()
        base = AsyncEngineArgs(model="facebook/opt-125m")
        extras = _json.dumps({
            "trust_remote_code": True,
            "max_num_seqs": 32,
        })
        out = servicer._apply_engine_args(base, extras)
        self.assertTrue(out.trust_remote_code)
        self.assertEqual(out.max_num_seqs, 32)
        # untouched fields preserved
        self.assertEqual(out.model, "facebook/opt-125m")

    def test_apply_engine_args_unknown_key_raises(self):
        """
        Tests _apply_engine_args rejects unknown keys with a helpful suggestion.
        """
        import sys, os, json as _json
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        from vllm.engine.arg_utils import AsyncEngineArgs

        servicer = BackendServicer()
        base = AsyncEngineArgs(model="facebook/opt-125m")
        with self.assertRaises(ValueError) as ctx:
            servicer._apply_engine_args(base, _json.dumps({"trustremotecode": True}))
        self.assertIn("trustremotecode", str(ctx.exception))
        # close-match hint for the typo
        self.assertIn("trust_remote_code", str(ctx.exception))

    def test_apply_engine_args_empty_passthrough(self):
        """
        Tests that empty engine_args returns the base unchanged.
        """
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        from vllm.engine.arg_utils import AsyncEngineArgs

        servicer = BackendServicer()
        base = AsyncEngineArgs(model="facebook/opt-125m")
        self.assertIs(servicer._apply_engine_args(base, ""), base)
        self.assertIs(servicer._apply_engine_args(base, None), base)

    def test_tokenize_string(self):
        """
        Tests the TokenizeString RPC returns valid tokens.
        """
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.LoadModel(backend_pb2.ModelOptions(Model="facebook/opt-125m"))
                self.assertTrue(response.success)
                resp = stub.TokenizeString(backend_pb2.PredictOptions(Prompt="Hello world"))
                self.assertGreater(resp.length, 0)
                self.assertEqual(len(resp.tokens), resp.length)
        except Exception as err:
            print(err)
            self.fail("TokenizeString service failed")
        finally:
            self.tearDown()

    def test_free(self):
        """
        Tests the Free RPC doesn't crash.
        """
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.LoadModel(backend_pb2.ModelOptions(Model="facebook/opt-125m"))
                self.assertTrue(response.success)
                free_resp = stub.Free(backend_pb2.HealthMessage())
                self.assertTrue(free_resp.success)
        except Exception as err:
            print(err)
            self.fail("Free service failed")
        finally:
            self.tearDown()

    def test_embedding(self):
        """
        This method tests if the embeddings are generated successfully
        """
        try:
            self.setUp()
            with grpc.insecure_channel("localhost:50051") as channel:
                stub = backend_pb2_grpc.BackendStub(channel)
                response = stub.LoadModel(backend_pb2.ModelOptions(Model="intfloat/e5-mistral-7b-instruct"))
                self.assertTrue(response.success)
                embedding_request = backend_pb2.PredictOptions(Embeddings="This is a test sentence.")
                embedding_response = stub.Embedding(embedding_request)
                self.assertIsNotNone(embedding_response.embeddings)
                # assert that is a list of floats
                self.assertIsInstance(embedding_response.embeddings, list)
                # assert that the list is not empty
                self.assertTrue(len(embedding_response.embeddings) > 0)
        except Exception as err:
            print(err)
            self.fail("Embedding service failed")
        finally:
            self.tearDown()


class TestStreamingToolParser(unittest.TestCase):
    """
    Server-less unit tests for the streaming + tool-parser machinery in
    BackendServicer._predict. These tests instantiate BackendServicer
    directly and mock the vLLM engine + tool parser, so they do not need
    a GPU, a model, or a running gRPC server. Kept in a separate class to
    avoid the parent setUp() which spawns a subprocess.

    Covers #582 (follow-up to #10346):
      1. Markup-leak prevention with a non-streaming parser (buffer fallback)
      2. No content duplication on the plain-text path with the buffer fallback
      3. Native streaming progressive plain-text emission
      4. Native streaming structured tool_call, no markup leak
      5. Parser exception → graceful fallback to buffer, still no markup
      6. No-tool-parser regression: unchanged per-delta content stream
    """

    @staticmethod
    def _make_generate(chunks):
        """Build a fake vLLM engine.generate that yields cumulative chunks."""
        from types import SimpleNamespace
        async def gen(*a, **k):
            for i, t in enumerate(chunks):
                yield SimpleNamespace(
                    outputs=[SimpleNamespace(
                        text=t,
                        token_ids=list(range(i + 1)),
                        logprobs=None,
                    )],
                    prompt_token_ids=[0],
                )
        return lambda *a, **k: gen()

    @staticmethod
    def _collect(servicer, req):
        import asyncio
        async def run():
            return [r async for r in servicer._predict(req, None, streaming=True)]
        return asyncio.run(run())

    def _new_servicer(self):
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        s = BackendServicer()
        s.reasoning_parser_cls = None
        s.tool_parser_cls = None
        s.tokenizer = None
        return s

    # ── Case 1+2: parser without streaming method → buffer fallback ──
    def test_buffer_path_no_markup_no_duplication(self):
        from types import SimpleNamespace

        def parser_cls(called, content_text, calls):
            class _P:
                def __init__(self, tokenizer, tools=None):
                    pass
                # NOTE: NO extract_tool_calls_streaming → takes the buffer path
                def extract_tool_calls(self, c, request=None):
                    return SimpleNamespace(
                        tools_called=called, content=content_text, tool_calls=calls,
                    )
            return _P

        tools_json = '[{"type":"function","function":{"name":"calc","parameters":{}}}]'

        # Tool-call case: no raw markup in any delta.content
        s = self._new_servicer()
        s.llm = SimpleNamespace(generate=self._make_generate([
            '<tool_call>\n{"name": "calc"',
            '<tool_call>\n{"name": "calc", "arguments": {"x": 1}}\n</tool_call>',
        ]))
        call = SimpleNamespace(id="call_1",
                               function=SimpleNamespace(name="calc", arguments='{"x": 1}'))
        s.tool_parser_cls = parser_cls(True, "", [call])
        req = backend_pb2.PredictOptions(Prompt="x", Tools=tools_json)
        replies = self._collect(s, req)
        contents = [cd.content for r in replies for cd in r.chat_deltas if cd.content]
        self.assertFalse(
            any("<tool_call" in c for c in contents),
            f"markup leaked: {contents!r}",
        )
        names = [tc.name for r in replies for cd in r.chat_deltas for tc in cd.tool_calls]
        self.assertIn("calc", names, "tool_call missing from final chunk")

        # Plain-text-with-tools case: full content delivered exactly once
        s2 = self._new_servicer()
        s2.llm = SimpleNamespace(generate=self._make_generate([
            "The capital ",
            "The capital of France is Paris.",
        ]))
        s2.tool_parser_cls = parser_cls(False, "", [])
        req2 = backend_pb2.PredictOptions(Prompt="x", Tools=tools_json)
        joined = "".join(
            cd.content for r in self._collect(s2, req2)
            for cd in r.chat_deltas if cd.content
        )
        self.assertEqual(
            joined.count("The capital of France is Paris."), 1,
            f"buffered content duplicated: {joined!r}",
        )

    # ── Case 3: native streaming, progressive plain text ──
    def test_native_streaming_progressive_plain_text(self):
        from types import SimpleNamespace

        class _DeltaMsg:
            def __init__(self, content=None, reasoning=None, tool_calls=None):
                self.content = content
                self.reasoning = reasoning
                self.tool_calls = tool_calls or []

        class StreamingParser:
            def __init__(self, tokenizer, tools=None):
                pass
            def extract_tool_calls(self, c, request=None):
                # Should NOT be called when native streaming runs successfully.
                raise AssertionError("extract_tool_calls invoked on native-streaming path")
            def extract_tool_calls_streaming(
                self, previous_text, current_text, delta_text,
                previous_token_ids, current_token_ids, delta_token_ids, request,
            ):
                if not delta_text:
                    return None
                return _DeltaMsg(content=delta_text)

        s = self._new_servicer()
        s.llm = SimpleNamespace(generate=self._make_generate([
            "Paris ",
            "Paris is ",
            "Paris is the capital of France.",
        ]))
        s.tool_parser_cls = StreamingParser
        req = backend_pb2.PredictOptions(
            Prompt="x",
            Tools='[{"type":"function","function":{"name":"calc","parameters":{}}}]',
        )
        replies = self._collect(s, req)

        intermediate_content = [
            cd.content for r in replies[:-1] for cd in r.chat_deltas if cd.content
        ]
        self.assertTrue(
            len(intermediate_content) > 0,
            "Plain-text response not streamed progressively (native streaming inactive?)",
        )
        assembled = "".join(
            cd.content for r in replies for cd in r.chat_deltas if cd.content
        )
        self.assertEqual(
            assembled, "Paris is the capital of France.",
            f"Assembled content wrong: {assembled!r}",
        )

    # ── Case 4: native streaming, structured tool_call, no markup ──
    def test_native_streaming_tool_call_no_markup_leak(self):
        from types import SimpleNamespace

        class _DeltaMsg:
            def __init__(self, content=None, reasoning=None, tool_calls=None):
                self.content = content
                self.reasoning = reasoning
                self.tool_calls = tool_calls or []

        class _ToolCallStreamer:
            def __init__(self, tokenizer, tools=None):
                self._emitted = False
            def extract_tool_calls(self, c, request=None):
                raise AssertionError("extract_tool_calls invoked on native-streaming path")
            def extract_tool_calls_streaming(
                self, previous_text, current_text, delta_text,
                previous_token_ids, current_token_ids, delta_token_ids, request,
            ):
                if "</tool_call>" in current_text and not self._emitted:
                    self._emitted = True
                    fn = SimpleNamespace(name="calc", arguments='{"x": 1}')
                    tc = SimpleNamespace(id="call_1", type="function", index=0, function=fn)
                    return _DeltaMsg(tool_calls=[tc])
                return None

        s = self._new_servicer()
        s.llm = SimpleNamespace(generate=self._make_generate([
            '<tool_call>\n',
            '<tool_call>\n{"name": "calc"',
            '<tool_call>\n{"name": "calc", "arguments": {"x": 1}}\n</tool_call>',
        ]))
        s.tool_parser_cls = _ToolCallStreamer
        req = backend_pb2.PredictOptions(
            Prompt="x",
            Tools='[{"type":"function","function":{"name":"calc","parameters":{}}}]',
        )
        replies = self._collect(s, req)

        contents = [cd.content for r in replies for cd in r.chat_deltas if cd.content]
        self.assertFalse(
            any("<tool_call" in c or "</tool_call>" in c for c in contents),
            f"markup leaked as content: {contents!r}",
        )
        names = [tc.name for r in replies for cd in r.chat_deltas for tc in cd.tool_calls if tc.name]
        args  = [tc.arguments for r in replies for cd in r.chat_deltas for tc in cd.tool_calls if tc.arguments]
        self.assertIn("calc", names, f"tool_call name missing; got {names!r}")
        self.assertIn('{"x": 1}', args, f"tool_call args missing; got {args!r}")

    # ── Case 5: parser exception → fallback to buffer, no leak ──
    def test_native_streaming_parser_exception_falls_back_to_buffer(self):
        from types import SimpleNamespace
        call = SimpleNamespace(id="call_1",
                               function=SimpleNamespace(name="calc", arguments='{"x": 1}'))

        class _BrokenStreamer:
            def __init__(self, tokenizer, tools=None):
                pass
            def extract_tool_calls(self, c, request=None):
                return SimpleNamespace(tools_called=True, content="", tool_calls=[call])
            def extract_tool_calls_streaming(self, *a, **kw):
                raise RuntimeError("simulated parser bug")

        s = self._new_servicer()
        s.llm = SimpleNamespace(generate=self._make_generate([
            '<tool_call>\n{"name": "calc"',
            '<tool_call>\n{"name": "calc", "arguments": {"x": 1}}\n</tool_call>',
        ]))
        s.tool_parser_cls = _BrokenStreamer
        req = backend_pb2.PredictOptions(
            Prompt="x",
            Tools='[{"type":"function","function":{"name":"calc","parameters":{}}}]',
        )
        replies = self._collect(s, req)

        contents = [cd.content for r in replies for cd in r.chat_deltas if cd.content]
        self.assertFalse(
            any("<tool_call" in c for c in contents),
            f"markup leaked after parser exception: {contents!r}",
        )
        names = [tc.name for r in replies for cd in r.chat_deltas for tc in cd.tool_calls]
        self.assertIn("calc", names, "tool_call missing from final chunk after fallback")

    # ── Case 6: no tool parser → unchanged per-delta content stream ──
    def test_no_tool_parser_unchanged_per_delta_stream(self):
        from types import SimpleNamespace
        s = self._new_servicer()  # tool_parser_cls already None
        s.llm = SimpleNamespace(generate=self._make_generate([
            "Hello ", "Hello world", "Hello world!",
        ]))
        req = backend_pb2.PredictOptions(Prompt="x", Tools="")
        replies = self._collect(s, req)

        intermediate = [
            cd.content for r in replies[:-1] for cd in r.chat_deltas if cd.content
        ]
        self.assertEqual(
            intermediate, ["Hello ", "world", "!"],
            f"plain streaming changed; got {intermediate!r}",
        )


class TestReasoningSplit(unittest.TestCase):
    """Server-less tests for BackendServicer._split_reasoning.

    vLLM's BaseThinkingReasoningParser returns the whole completion as
    reasoning and None as content whenever the end token is missing. Taken
    literally that duplicates a thinking-disabled answer into both fields.
    """

    class _Parser:
        start_token = "<think>"
        end_token = "</think>"

    def _split(self, generated, prompt, reasoning, content):
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        return BackendServicer._split_reasoning(
            self._Parser(), generated, prompt, reasoning, content,
        )

    def test_thinking_off_is_not_duplicated_into_reasoning(self):
        """No tags anywhere: the answer is content, and only content."""
        r, c = self._split(
            "391", "user: 17*23?\n<think>\n\n</think>\n\n",
            reasoning="391", content=None,
        )
        self.assertEqual(r, "")
        self.assertEqual(c, "391")

    def test_prefilled_start_tag_keeps_truncated_reasoning(self):
        """Prompt left the block open and the end token never arrived
        (budget exhausted): that really is all reasoning."""
        r, c = self._split(
            "thinking and thinking", "user: hi\n<think>\n",
            reasoning="thinking and thinking", content=None,
        )
        self.assertEqual(r, "thinking and thinking")
        self.assertEqual(c, "")

    def test_end_token_present_keeps_parser_split(self):
        r, c = self._split(
            "adding two and two</think>4", "user: hi\n<think>\n",
            reasoning="adding two and two", content="4",
        )
        self.assertEqual(r, "adding two and two")
        self.assertEqual(c, "4")

    def test_stop_right_after_end_token_yields_empty_content(self):
        """Content must not fall back to the raw text — that would put the
        reasoning into the answer."""
        r, c = self._split(
            "reasoned</think>", "user: hi\n<think>\n",
            reasoning="reasoned", content=None,
        )
        self.assertEqual(r, "reasoned")
        self.assertEqual(c, "")

    def test_unknown_token_layout_keeps_previous_behaviour(self):
        class _Bare:
            pass
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        r, c = BackendServicer._split_reasoning(
            _Bare(), "raw", "prompt", "raw", None,
        )
        self.assertEqual(r, "raw")
        self.assertEqual(c, "raw")


class TestReasoningParserConstruction(unittest.TestCase):
    """The parser must learn whether thinking was on for this request.

    vLLM's engine-based parsers (Qwen3Parser and friends) read
    chat_template_kwargs["enable_thinking"] and default to True, so a parser
    built without it treats a thinking-disabled completion as pure reasoning.
    """

    def _servicer(self):
        import sys, os
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        s = BackendServicer()
        s.tokenizer = object()
        return s

    def test_chat_template_kwargs_are_forwarded(self):
        seen = {}

        class _Parser:
            def __init__(self, tokenizer, **kwargs):
                seen.update(kwargs)

        s = self._servicer()
        s.reasoning_parser_cls = _Parser
        s._new_reasoning_parser({"enable_thinking": False})
        self.assertEqual(
            seen.get("chat_template_kwargs"), {"enable_thinking": False},
        )

    def test_parser_without_the_kwarg_still_builds(self):
        """Older parsers take only the tokenizer — must not break them."""
        class _Old:
            def __init__(self, tokenizer):
                self.tokenizer = tokenizer

        s = self._servicer()
        s.reasoning_parser_cls = _Old
        self.assertIsInstance(
            s._new_reasoning_parser({"enable_thinking": False}), _Old,
        )


class TestStreamingReasoningSplit(unittest.TestCase):
    """With a reasoning parser, streaming must split reasoning from content.

    The stream used to send each raw text delta as ChatDelta.content, so with
    thinking on the reasoning text arrived as delta.content and the final
    chunk repeated it as reasoning_content. These tests replace the engine
    and vLLM's composed parser (ParserManager.get_parser) with fakes; no GPU,
    model or server needed.
    """

    THINK = ["Let me ", "count the ", "primes.", "</think>"]
    ANSWER = ["There are ", "37 primes."]

    def setUp(self):
        from types import SimpleNamespace
        from unittest.mock import patch
        import backend

        def parser_request(model, messages, tools=None):
            return SimpleNamespace(
                model=model, messages=messages,
                tools=[SimpleNamespace(function=SimpleNamespace(**tool["function"]))
                       for tool in tools] if tools else None,
            )

        # These fake-parser tests also run on backend profiles whose vLLM
        # predates ParserManager and therefore has no _ParserRequest import.
        request_patch = patch.object(backend, "_ParserRequest", parser_request, create=True)
        request_patch.start()
        self.addCleanup(request_patch.stop)

    class _DeltaMsg:
        def __init__(self, content=None, reasoning=None, tool_calls=None):
            self.content = content
            self.reasoning = reasoning
            self.tool_calls = tool_calls or []

    @classmethod
    def _parser_cls(cls, seen=None, fail_after=None):
        delta_msg = cls._DeltaMsg

        class _Parser:
            """Stands in for vLLM's DelegatingParser: reasoning until the
            end tag, then content, then a tool call between <tool_call> tags
            (name first, arguments as they arrive)."""
            def __init__(self, tokenizer, tools=None, **kwargs):
                if seen is not None:
                    seen.update(kwargs, tools=tools)
                self._state = "reasoning"
                self._calls = 0

            def parse_delta(self, delta_text, delta_token_ids, request,
                            prompt_token_ids=None, *, finished):
                from types import SimpleNamespace
                self._calls += 1
                if fail_after is not None and self._calls > fail_after:
                    raise RuntimeError("simulated parser bug")
                if self._state == "reasoning":
                    if "</think>" in delta_text:
                        self._state = "content"
                        before = delta_text.split("</think>", 1)[0]
                        return delta_msg(reasoning=before) if before else None
                    return delta_msg(reasoning=delta_text)
                if delta_text == "<tool_call>":
                    self._state = "tool"
                    fn = SimpleNamespace(name="search", arguments="")
                    return delta_msg(tool_calls=[SimpleNamespace(index=0, id="call_1", function=fn)])
                if self._state == "tool":
                    if delta_text == "</tool_call>":
                        return None
                    fn = SimpleNamespace(name=None, arguments=delta_text)
                    return delta_msg(tool_calls=[SimpleNamespace(index=0, id=None, function=fn)])
                return delta_msg(content=delta_text)
        return _Parser

    class _ToolParser:
        """Full-text tool extraction used after a streaming parser failure."""
        def __init__(self, tokenizer, tools=None):
            pass

        def extract_tool_calls(self, text, request=None):
            from types import SimpleNamespace
            if "<tool_call>" not in text:
                return SimpleNamespace(tools_called=False, content=text, tool_calls=[])
            before, rest = text.split("<tool_call>", 1)
            args = rest.split("</tool_call>", 1)[0]
            call = SimpleNamespace(id="call_1", function=SimpleNamespace(name="search", arguments=args))
            return SimpleNamespace(tools_called=True, content=before, tool_calls=[call])

    class _ReasoningParser:
        """Full-text split used after the loop (BaseThinkingReasoningParser shape)."""
        start_token = "<think>"
        end_token = "</think>"

        def __init__(self, tokenizer, **kwargs):
            pass

        def extract_reasoning(self, text, request=None):
            if "</think>" in text:
                r, c = text.split("</think>", 1)
                return r, c
            return text, None

    def _servicer(self, stream_parser_cls, pieces=None):
        import sys, os
        from types import SimpleNamespace
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        from backend import BackendServicer
        s = BackendServicer()
        s.tokenizer = None
        s.tool_parser_cls = self._ToolParser
        s.reasoning_parser_cls = self._ReasoningParser
        s.stream_parser_cls = stream_parser_cls
        s.llm = SimpleNamespace(generate=TestStreamingToolParser._make_generate(
            self._cumulative(pieces or (self.THINK + self.ANSWER))))
        return s

    @staticmethod
    def _cumulative(pieces):
        out, acc = [], ""
        for p in pieces:
            acc += p
            out.append(acc)
        return out

    @staticmethod
    def _joined(replies, field):
        return "".join(getattr(cd, field) for r in replies for cd in r.chat_deltas)

    def test_reasoning_is_not_streamed_as_content(self):
        s = self._servicer(self._parser_cls())
        replies = TestStreamingToolParser._collect(s, backend_pb2.PredictOptions(Prompt="x"))
        self.assertEqual(self._joined(replies, "content"), "There are 37 primes.")
        self.assertEqual(self._joined(replies, "reasoning_content"), "Let me count the primes.")
        # Progressive: reasoning and content arrive before the final chunk.
        self.assertTrue(any(cd.reasoning_content for r in replies[:-1] for cd in r.chat_deltas))
        self.assertTrue(any(cd.content for r in replies[:-1] for cd in r.chat_deltas))
        # The final chunk carries no text, otherwise LocalAI repeats it.
        final = replies[-1].chat_deltas[0]
        self.assertEqual((final.content, final.reasoning_content), ("", ""))

    def test_parser_error_mid_stream_sends_the_rest_once(self):
        s = self._servicer(self._parser_cls(fail_after=2))
        replies = TestStreamingToolParser._collect(s, backend_pb2.PredictOptions(Prompt="x"))
        self.assertEqual(self._joined(replies, "content"), "There are 37 primes.")
        self.assertEqual(self._joined(replies, "reasoning_content"), "Let me count the primes.")

    def test_without_stream_parser_streams_raw_deltas(self):
        """vLLM without ParserManager: previous behaviour."""
        s = self._servicer(None)
        replies = TestStreamingToolParser._collect(s, backend_pb2.PredictOptions(Prompt="x"))
        intermediate = "".join(cd.content for r in replies[:-1] for cd in r.chat_deltas)
        self.assertEqual(intermediate, "".join(self.THINK + self.ANSWER))

    def test_parser_gets_chat_template_kwargs_and_tools(self):
        seen = {}
        s = self._servicer(self._parser_cls(seen=seen))
        tools = '[{"type":"function","function":{"name":"calc","parameters":{}}}]'
        parser, parser_request = s._new_stream_parser(
            backend_pb2.PredictOptions(Prompt="x", Tools=tools),
            {"tokenize": False, "add_generation_prompt": True, "enable_thinking": False,
             "tools": [{}]},
        )
        self.assertIsNotNone(parser)
        self.assertEqual(seen["chat_template_kwargs"], {"enable_thinking": False})
        self.assertEqual([t.function.name for t in seen["tools"]], ["calc"])

    def test_parser_error_after_partial_tool_arguments(self):
        """The rest of the arguments follows on the same index; no raw
        tool-call markup reaches content."""
        pieces = self.THINK + ["Checking.", "<tool_call>", '{"q": ', '"primes"}', "</tool_call>"]
        tools = '[{"type":"function","function":{"name":"search","parameters":{}}}]'
        for fail_after in (6, 7):  # after the name / after part of the arguments
            with self.subTest(fail_after=fail_after):
                s = self._servicer(self._parser_cls(fail_after=fail_after), pieces)
                replies = TestStreamingToolParser._collect(
                    s, backend_pb2.PredictOptions(Prompt="x", Tools=tools))
                self.assertEqual(self._joined(replies, "content"), "Checking.")
                self.assertEqual(self._joined(replies, "reasoning_content"), "Let me count the primes.")
                calls = [tc for r in replies for cd in r.chat_deltas for tc in cd.tool_calls]
                self.assertEqual({tc.index for tc in calls}, {0})
                self.assertEqual([tc.name for tc in calls if tc.name], ["search"])
                self.assertEqual("".join(tc.arguments for tc in calls), '{"q": "primes"}')