test(agent): cover pluginized agent runner runtime

src/langbot/pkg/agent/runner/registry.py

@@ -146,8 +146,10 @@ class AgentRunnerRegistry:
         Returns:
             List of runner descriptors
         """
-        if use_cache and self._cache is not None:
-            # Filter from cache
+        if use_cache and self._cache is not None and self._cache:
+            # Filter from cache. Do not treat an empty cache as final because the
+            # plugin runtime may still be launching installed plugins when the
+            # first metadata request arrives.
             return self._filter_runners_by_bound_plugins(self._cache, bound_plugins)
 
         # Discover fresh (always full list)

src/langbot/pkg/persistence/alembic/versions/0006_normalize_mcp_remote_mode.py

@@ -10,7 +10,7 @@ ssereadtimeout) live in ``extra_args`` and are left untouched — the
 auto-detecting remote transport consumes them regardless.
 
 Revision ID: 0006_normalize_mcp_remote_mode
-Revises: 0005_add_llm_context_length
+Revises: 8d3a1f2c4b6e
 Create Date: 2026-06-21
 """
 
@@ -18,7 +18,7 @@ import sqlalchemy as sa
 from alembic import op
 
 revision = '0006_normalize_mcp_remote_mode'
-down_revision = '0005_add_llm_context_length'
+down_revision = '8d3a1f2c4b6e'
 branch_labels = None
 depends_on = None
 

tests/e2e/conftest.py

@@ -61,7 +61,7 @@ def langbot_process(e2e_config_path, e2e_port, e2e_tmpdir):
         project_root=project_root,
         work_dir=e2e_tmpdir,  # Run in tmpdir where data/config.yaml exists
         port=e2e_port,
-        timeout=60,  # Longer timeout for first startup
+        timeout=180,  # Longer timeout for first startup
         collect_coverage=collect_coverage,
     )
 

tests/e2e/test_agent_runner_plugin_runtime.py

@@ -0,0 +1,473 @@
+"""E2E tests for pluginized AgentRunner execution.
+
+This module starts the real LangBot backend with the plugin system enabled and
+loads a deterministic AgentRunner plugin through the real SDK Plugin Runtime.
+"""
+
+from __future__ import annotations
+
+import shutil
+import socket
+import sqlite3
+import subprocess
+import tempfile
+import textwrap
+import time
+from pathlib import Path
+
+import httpx
+import pytest
+
+from tests.e2e.utils.config_factory import create_minimal_config, create_test_directories
+from tests.e2e.utils.process_manager import LangBotProcess, find_project_root
+
+pytestmark = pytest.mark.e2e
+
+
+QA_RUNNER_ID = 'plugin:e2e/agent-runner-qa/default'
+QA_PLUGIN_DIRNAME = 'e2e__agent-runner-qa'
+
+
+@pytest.fixture(scope='session')
+def agent_runner_e2e_port():
+    """Port for the AgentRunner plugin-runtime E2E process."""
+    return 15310
+
+
+@pytest.fixture(scope='session')
+def agent_runner_e2e_tmpdir():
+    """Create temporary directory for AgentRunner E2E testing."""
+    tmpdir = Path(tempfile.mkdtemp(prefix='langbot_agent_runner_e2e_'))
+    yield tmpdir
+    shutil.rmtree(tmpdir, ignore_errors=True)
+
+
+def _write_qa_agent_runner_plugin(plugin_root: Path) -> None:
+    """Write a deterministic AgentRunner plugin used by this E2E."""
+    runner_dir = plugin_root / 'components' / 'agent_runner'
+    runner_dir.mkdir(parents=True, exist_ok=True)
+    (plugin_root / 'assets').mkdir(parents=True, exist_ok=True)
+    (plugin_root / 'assets' / 'icon.svg').write_text(
+        '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1 1"></svg>',
+        encoding='utf-8',
+    )
+    (plugin_root / 'manifest.yaml').write_text(
+        textwrap.dedent(
+            """
+            apiVersion: langbot/v1
+            kind: Plugin
+            metadata:
+              author: e2e
+              name: agent-runner-qa
+              version: 0.1.0
+              label:
+                en_US: AgentRunner QA
+                zh_Hans: AgentRunner QA
+              description:
+                en_US: Deterministic AgentRunner E2E probe.
+                zh_Hans: 确定性的 AgentRunner E2E 探针。
+              icon: assets/icon.svg
+            spec:
+              version: 0.1.0
+              config: []
+              components:
+                AgentRunner:
+                  fromDirs:
+                    - path: components/agent_runner/
+              pages: []
+            execution:
+              python:
+                path: main.py
+                attr: AgentRunnerQAPlugin
+            """
+        ).strip()
+        + '\n',
+        encoding='utf-8',
+    )
+    (plugin_root / 'main.py').write_text(
+        textwrap.dedent(
+            """
+            from __future__ import annotations
+
+            from langbot_plugin.api.definition.plugin import BasePlugin
+
+
+            class AgentRunnerQAPlugin(BasePlugin):
+                async def initialize(self) -> None:
+                    pass
+            """
+        ).strip()
+        + '\n',
+        encoding='utf-8',
+    )
+    (runner_dir / 'default.yaml').write_text(
+        textwrap.dedent(
+            """
+            apiVersion: langbot/v1
+            kind: AgentRunner
+            metadata:
+              name: default
+              label:
+                en_US: QA Echo Runner
+                zh_Hans: QA Echo Runner
+              description:
+                en_US: Echoes input and exercises run-scoped state APIs.
+                zh_Hans: 回显输入并验证运行级状态 API。
+            spec:
+              config: []
+              capabilities:
+                streaming: false
+              permissions: {}
+            execution:
+              python:
+                path: default.py
+                attr: DefaultAgentRunner
+            """
+        ).strip()
+        + '\n',
+        encoding='utf-8',
+    )
+    (runner_dir / 'default.py').write_text(
+        textwrap.dedent(
+            """
+            from __future__ import annotations
+
+            from typing import AsyncGenerator
+
+            from langbot_plugin.api.definition.components.agent_runner.runner import AgentRunner
+            from langbot_plugin.api.entities.builtin.agent_runner.context import AgentRunContext
+            from langbot_plugin.api.entities.builtin.agent_runner.result import AgentRunResult
+            from langbot_plugin.api.entities.builtin.provider.message import Message
+
+
+            class DefaultAgentRunner(AgentRunner):
+                async def run(self, ctx: AgentRunContext) -> AsyncGenerator[AgentRunResult, None]:
+                    text = ctx.input.to_text()
+                    yield AgentRunResult.message_completed(
+                        ctx.run_id,
+                        Message(role='assistant', content=f'e2e echo: {text}'),
+                    )
+                    yield AgentRunResult.state_updated(
+                        ctx.run_id,
+                        'e2e.echo_count',
+                        {'count': 1},
+                        scope='conversation',
+                    )
+                    yield AgentRunResult.run_completed(ctx.run_id, finish_reason='stop')
+            """
+        ).strip()
+        + '\n',
+        encoding='utf-8',
+    )
+
+
+def _free_port() -> int:
+    """Reserve a currently-free localhost TCP port for this E2E process."""
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+        sock.bind(('127.0.0.1', 0))
+        return int(sock.getsockname()[1])
+
+
+@pytest.fixture(scope='session')
+def agent_runner_runtime_ports():
+    """Control/debug ports for the standalone plugin runtime."""
+    control_port = _free_port()
+    debug_port = _free_port()
+    while debug_port == control_port:
+        debug_port = _free_port()
+    return control_port, debug_port
+
+
+@pytest.fixture(scope='session')
+def agent_runner_e2e_config_path(agent_runner_e2e_tmpdir, agent_runner_e2e_port, agent_runner_runtime_ports):
+    """Create a plugin-enabled config and deterministic AgentRunner fixture."""
+    config_path = create_minimal_config(agent_runner_e2e_tmpdir, port=agent_runner_e2e_port)
+    create_test_directories(agent_runner_e2e_tmpdir)
+
+    import yaml
+
+    with open(config_path, encoding='utf-8') as f:
+        config = yaml.safe_load(f)
+    config['api']['global_api_key'] = 'e2e-agent-runner-key'
+    runtime_control_port, _runtime_debug_port = agent_runner_runtime_ports
+    config['plugin']['enable'] = True
+    config['plugin']['runtime_ws_url'] = f'ws://127.0.0.1:{runtime_control_port}/control/ws'
+    config['plugin']['enable_marketplace'] = False
+    config['box']['enabled'] = False
+    config['system']['jwt']['secret'] = 'e2e-agent-runner-secret-key'
+    with open(config_path, 'w', encoding='utf-8') as f:
+        yaml.safe_dump(config, f, default_flow_style=False)
+
+    _write_qa_agent_runner_plugin(agent_runner_e2e_tmpdir / 'data' / 'plugins' / QA_PLUGIN_DIRNAME)
+    return config_path
+
+
+@pytest.fixture(scope='session')
+def agent_runner_runtime_process(agent_runner_e2e_tmpdir, agent_runner_runtime_ports):
+    """Start the real SDK plugin runtime over WebSocket."""
+    control_port, debug_port = agent_runner_runtime_ports
+    stdout_path = agent_runner_e2e_tmpdir / 'plugin-runtime.stdout.log'
+    stderr_path = agent_runner_e2e_tmpdir / 'plugin-runtime.stderr.log'
+    stdout_file = open(stdout_path, 'wb')
+    stderr_file = open(stderr_path, 'wb')
+    proc = subprocess.Popen(
+        [
+            str(find_project_root() / '.venv' / 'bin' / 'python'),
+            '-m',
+            'langbot_plugin.cli.__init__',
+            'rt',
+            '--ws-control-port',
+            str(control_port),
+            '--ws-debug-port',
+            str(debug_port),
+        ],
+        cwd=agent_runner_e2e_tmpdir,
+        stdout=stdout_file,
+        stderr=stderr_file,
+        start_new_session=True,
+    )
+    yield proc
+    proc.terminate()
+    try:
+        proc.wait(timeout=5)
+    except subprocess.TimeoutExpired:
+        proc.kill()
+        proc.wait()
+    stdout_file.close()
+    stderr_file.close()
+
+
+@pytest.fixture(scope='session')
+def agent_runner_langbot_process(
+    agent_runner_e2e_config_path,
+    agent_runner_e2e_port,
+    agent_runner_e2e_tmpdir,
+    agent_runner_runtime_process,
+):
+    """Start real LangBot with plugin runtime enabled."""
+    project_root = find_project_root()
+    proc = LangBotProcess(
+        project_root=project_root,
+        work_dir=agent_runner_e2e_tmpdir,
+        port=agent_runner_e2e_port,
+        timeout=180,
+        debug=True,
+        cli_args=['--standalone-runtime'],
+    )
+
+    success = proc.start()
+    if not success:
+        stdout, stderr = proc.get_logs()
+        pytest.fail(f'LangBot failed to start with AgentRunner plugin runtime:\nstdout: {stdout}\nstderr: {stderr}')
+
+    yield proc
+
+    proc.stop()
+
+
+@pytest.fixture
+def agent_runner_client(agent_runner_e2e_port, agent_runner_langbot_process):
+    """HTTP client for the AgentRunner E2E backend."""
+    with httpx.Client(
+        base_url=f'http://127.0.0.1:{agent_runner_e2e_port}',
+        timeout=90.0,
+        trust_env=False,
+    ) as client:
+        yield client
+
+
+def _init_and_auth(client: httpx.Client) -> str:
+    """Initialize the test admin user and return a bearer token."""
+    init_resp = client.post('/api/v1/user/init', json={'user': 'admin', 'password': 'admin'})
+    assert init_resp.status_code == 200
+    assert init_resp.json()['code'] in [0, 1]
+
+    auth_resp = client.post('/api/v1/user/auth', json={'user': 'admin', 'password': 'admin'})
+    assert auth_resp.status_code == 200
+    payload = auth_resp.json()
+    assert payload['code'] == 0
+    return payload['data']['token']
+
+
+def test_plugin_runtime_discovers_agent_runner(agent_runner_client, agent_runner_langbot_process):
+    """Pipeline metadata should include the real runtime-discovered QA runner."""
+    token = _init_and_auth(agent_runner_client)
+    start = time.time()
+    while time.time() - start < 60:
+        response = agent_runner_client.get(
+            '/api/v1/pipelines/_/metadata',
+            headers={'Authorization': f'Bearer {token}'},
+        )
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data['code'] == 0
+        metadata_groups = data['data']['configs']
+        ai_metadata = next(group for group in metadata_groups if group.get('name') == 'ai')
+
+        runner_stage = next(stage for stage in ai_metadata['stages'] if stage['name'] == 'runner')
+        runner_select = next(item for item in runner_stage['config'] if item['name'] == 'id')
+        option_names = {option['name'] for option in runner_select['options']}
+        if QA_RUNNER_ID in option_names:
+            return
+        time.sleep(2)
+
+    assert QA_RUNNER_ID in option_names
+
+def test_host_orchestrator_runs_agent_runner_and_records_ledger(
+    agent_runner_e2e_config_path,
+    agent_runner_e2e_tmpdir,
+    agent_runner_runtime_process,
+):
+    """The Host orchestrator should run the pluginized runner and persist run side effects."""
+    import asyncio
+    import os
+
+    from langbot.pkg.agent.runner.host_models import (
+        AgentBinding,
+        AgentEventEnvelope,
+        BindingScope,
+        DeliveryPolicy,
+        StatePolicy,
+    )
+    from langbot.pkg.core import boot
+    from langbot.pkg.utils import platform as platform_utils
+    from langbot_plugin.api.entities.builtin.agent_runner.delivery import DeliveryContext
+    from langbot_plugin.api.entities.builtin.agent_runner.event import ActorContext, SubjectContext
+    from langbot_plugin.api.entities.builtin.agent_runner.input import AgentInput
+
+    async def _run_probe():
+        previous_cwd = Path.cwd()
+        previous_standalone_runtime = platform_utils.standalone_runtime
+        os.chdir(agent_runner_e2e_tmpdir)
+        platform_utils.standalone_runtime = True
+        ap = None
+        try:
+            ap = await boot.make_app(asyncio.get_running_loop())
+            for _ in range(60):
+                handler = getattr(ap.plugin_connector, 'handler', None)
+                if handler is not None:
+                    await handler.ping()
+                    break
+                await asyncio.sleep(1)
+            else:
+                raise AssertionError('Plugin runtime did not connect')
+
+            for _ in range(60):
+                runners = await ap.agent_runner_registry.list_runners(use_cache=False)
+                if any(runner.id == QA_RUNNER_ID for runner in runners):
+                    break
+                await asyncio.sleep(1)
+            else:
+                raise AssertionError(f'{QA_RUNNER_ID} was not discovered')
+
+            event = AgentEventEnvelope(
+                event_id='e2e-orchestrator-event-001',
+                event_type='message.received',
+                source='api',
+                conversation_id='e2e-conversation',
+                thread_id='e2e-thread',
+                actor=ActorContext(actor_type='user', actor_id='user-001', actor_name='E2E User'),
+                subject=SubjectContext(subject_type='chat', subject_id='chat-001'),
+                input=AgentInput(text='hello from orchestrator e2e'),
+                delivery=DeliveryContext(surface='e2e'),
+            )
+            binding = AgentBinding(
+                binding_id='e2e-binding',
+                scope=BindingScope(scope_type='global'),
+                runner_id=QA_RUNNER_ID,
+                state_policy=StatePolicy(enable_state=True, state_scopes=['conversation']),
+                delivery_policy=DeliveryPolicy(enable_streaming=False, enable_reply=True),
+            )
+            return [message async for message in ap.agent_run_orchestrator.run(event, binding)]
+        finally:
+            if ap is not None:
+                ap.dispose()
+            platform_utils.standalone_runtime = previous_standalone_runtime
+            os.chdir(previous_cwd)
+
+    messages = asyncio.run(_run_probe())
+
+    assert len(messages) == 1
+    assert messages[0].role == 'assistant'
+    assert messages[0].content == 'e2e echo: hello from orchestrator e2e'
+
+    db_path = agent_runner_e2e_tmpdir / 'data' / 'langbot.db'
+    conn = sqlite3.connect(str(db_path))
+    try:
+        run_row = conn.execute(
+            "SELECT status, runner_id FROM agent_run WHERE event_id = 'e2e-orchestrator-event-001'"
+        ).fetchone()
+        assert run_row == ('completed', QA_RUNNER_ID)
+
+        event_types = {
+            row[0]
+            for row in conn.execute(
+                "SELECT type FROM agent_run_event WHERE run_id = (SELECT run_id FROM agent_run WHERE event_id = 'e2e-orchestrator-event-001')"
+            ).fetchall()
+        }
+        assert {'state.updated', 'message.completed', 'run.completed'}.issubset(event_types)
+
+        state_row = conn.execute(
+            "SELECT value_json FROM agent_runner_state WHERE state_key = 'e2e.echo_count'"
+        ).fetchone()
+        assert state_row is not None
+        assert '"count": 1' in state_row[0]
+    finally:
+        conn.close()
+
+
+def test_pluginized_agent_runner_executes_through_runtime(agent_runner_client, agent_runner_langbot_process):
+    """The Host debug surface should invoke the QA runner through the real Plugin Runtime."""
+    token = _init_and_auth(agent_runner_client)
+    start = time.time()
+    while time.time() - start < 60:
+        metadata_response = agent_runner_client.get(
+            '/api/v1/pipelines/_/metadata',
+            headers={'Authorization': f'Bearer {token}'},
+        )
+        assert metadata_response.status_code == 200
+        metadata = metadata_response.json()['data']['configs']
+        ai_metadata = next(group for group in metadata if group.get('name') == 'ai')
+        runner_stage = next(stage for stage in ai_metadata['stages'] if stage['name'] == 'runner')
+        runner_select = next(item for item in runner_stage['config'] if item['name'] == 'id')
+        if QA_RUNNER_ID in {option['name'] for option in runner_select['options']}:
+            break
+        time.sleep(2)
+    else:
+        pytest.fail(f'{QA_RUNNER_ID} was not discovered before run_agent')
+
+    response = agent_runner_client.post(
+        '/api/v1/system/debug/plugin/action',
+        headers={'Authorization': f'Bearer {token}'},
+        json={
+            'action': 'run_agent',
+            'timeout': 60,
+            'data': {
+                'plugin_author': 'e2e',
+                'plugin_name': 'agent-runner-qa',
+                'runner_name': 'default',
+                'context': {
+                    'run_id': 'e2e-run-001',
+                    'trigger': {'type': 'message.received'},
+                    'event': {
+                        'event_id': 'e2e-event-001',
+                        'event_type': 'message.received',
+                        'source': 'api',
+                    },
+                    'input': {'text': 'hello from real e2e'},
+                    'delivery': {'surface': 'e2e'},
+                    'resources': {},
+                    'runtime': {},
+                },
+            },
+        },
+    )
+
+    assert response.status_code == 200
+    payload = response.json()
+    assert payload['code'] == 0
+    result = payload['data']
+    assert result['type'] == 'message.completed', result
+    assert result['data']['message']['role'] == 'assistant'
+    assert result['data']['message']['content'] == 'e2e echo: hello from real e2e'

tests/e2e/utils/config_factory.py

@@ -141,6 +141,27 @@ def create_minimal_config(tmpdir: Path, port: int = 15300) -> Path:
                 'delete_batch_size': 1000,
             },
         },
+        'box': {
+            'enabled': False,
+            'backend': 'local',
+            'runtime': {
+                'endpoint': '',
+            },
+            'local': {
+                'profile': 'default',
+                'image': '',
+                'host_root': str(tmpdir / 'box'),
+                'default_workspace': '',
+                'skills_root': 'skills',
+                'allowed_mount_roots': [str(tmpdir / 'box'), '/tmp'],
+                'workspace_quota_mb': None,
+            },
+            'e2b': {
+                'api_key': '',
+                'api_url': '',
+                'template': '',
+            },
+        },
         'space': {
             'url': 'https://space.langbot.app',
             'models_gateway_api_url': 'https://api.langbot.cloud/v1',
@@ -168,8 +189,12 @@ def create_test_directories(tmpdir: Path) -> dict[str, Path]:
     """Create necessary directories for LangBot testing."""
     directories = {
         'data': tmpdir / 'data',
+        'labels': tmpdir / 'data' / 'labels',
+        'metadata': tmpdir / 'data' / 'metadata',
         'logs': tmpdir / 'logs',
+        'data_logs': tmpdir / 'data' / 'logs',
         'storage': tmpdir / 'storage',
+        'box': tmpdir / 'box',
         'chroma': tmpdir / 'chroma',
     }
 

tests/e2e/utils/process_manager.py

@@ -9,6 +9,7 @@ import subprocess
 import time
 import signal
 import os
+import sys
 from pathlib import Path
 from typing import Optional
 import logging
@@ -26,13 +27,21 @@ class LangBotProcess:
         port: int = 15300,
         timeout: int = 30,
         collect_coverage: bool = True,
+        debug: bool = False,
+        cli_args: list[str] | None = None,
     ):
         self.project_root = project_root
         self.work_dir = work_dir  # Directory containing data/config.yaml
         self.port = port
         self.timeout = timeout
         self.collect_coverage = collect_coverage
+        self.debug = debug
+        self.cli_args = cli_args or []
         self.process: Optional[subprocess.Popen] = None
+        self._stdout_file = None
+        self._stderr_file = None
+        self._stdout_path = self.work_dir / 'langbot.stdout.log'
+        self._stderr_path = self.work_dir / 'langbot.stderr.log'
         self._stdout_data: bytes = b''
         self._stderr_data: bytes = b''
         self._coverage_file: Optional[Path] = None
@@ -63,13 +72,14 @@ class LangBotProcess:
         # Disable telemetry
         env['SPACE__DISABLE_TELEMETRY'] = 'true'
         env['SPACE__DISABLE_MODELS_SERVICE'] = 'true'
+        if self.debug:
+            env['DEBUG'] = 'true'
 
         # Build command
         if self.collect_coverage:
             # Use coverage.py to collect coverage data
             # Set COVERAGE_PROCESS_START to enable coverage in subprocess
             self._coverage_file = self.work_dir / '.coverage.e2e'
-            env['COVERAGE_PROCESS_START'] = str(self.project_root / '.coveragerc')
             env['COVERAGE_FILE'] = str(self._coverage_file)
 
             # Create .coveragerc for subprocess
@@ -88,27 +98,33 @@ precision = 2
             coveragerc_path = self.work_dir / '.coveragerc'
             with open(coveragerc_path, 'w') as f:
                 f.write(coveragerc_content)
+            env['COVERAGE_PROCESS_START'] = str(coveragerc_path)
 
             cmd = [
+                sys.executable,
+                '-m',
                 'coverage',
                 'run',
                 '--rcfile=' + str(coveragerc_path),
                 '-m',
                 'langbot',
+                *self.cli_args,
             ]
         else:
-            cmd = ['uv', 'run', 'python', '-m', 'langbot']
+            cmd = [sys.executable, '-m', 'langbot', *self.cli_args]
 
         logger.info(f'Starting LangBot in: {self.work_dir}')
         logger.info(f'Command: {cmd}')
 
         # Start process (run in work_dir so it finds data/config.yaml)
+        self._stdout_file = open(self._stdout_path, 'wb')
+        self._stderr_file = open(self._stderr_path, 'wb')
         self.process = subprocess.Popen(
             cmd,
             cwd=self.work_dir,
             env=env,
-            stdout=subprocess.PIPE,
-            stderr=subprocess.PIPE,
+            stdout=self._stdout_file,
+            stderr=self._stderr_file,
             preexec_fn=os.setsid if os.name != 'nt' else None,
         )
 
@@ -117,7 +133,14 @@ precision = 2
         while time.time() - start_time < self.timeout:
             # Check if process died
             if self.process.poll() is not None:
-                self._stdout_data, self._stderr_data = self.process.communicate()
+                if self._stdout_file:
+                    self._stdout_file.close()
+                    self._stdout_file = None
+                if self._stderr_file:
+                    self._stderr_file.close()
+                    self._stderr_file = None
+                self._stdout_data = self._stdout_path.read_bytes() if self._stdout_path.exists() else b''
+                self._stderr_data = self._stderr_path.read_bytes() if self._stderr_path.exists() else b''
                 logger.error(f'LangBot process died: {self._stderr_data.decode()}')
                 return False
 
@@ -170,8 +193,14 @@ precision = 2
             self.process.wait()
 
         # Collect output for debugging
-        if self.process.stdout or self.process.stderr:
-            self._stdout_data, self._stderr_data = self.process.communicate()
+        if self._stdout_file:
+            self._stdout_file.close()
+            self._stdout_file = None
+        if self._stderr_file:
+            self._stderr_file.close()
+            self._stderr_file = None
+        self._stdout_data = self._stdout_path.read_bytes() if self._stdout_path.exists() else b''
+        self._stderr_data = self._stderr_path.read_bytes() if self._stderr_path.exists() else b''
 
         self.process = None
 
@@ -183,6 +212,10 @@ precision = 2
         """Get stdout and stderr logs."""
         stdout = self._stdout_data.decode('utf-8', errors='replace')
         stderr = self._stderr_data.decode('utf-8', errors='replace')
+        if not stdout and self._stdout_path.exists():
+            stdout = self._stdout_path.read_text(encoding='utf-8', errors='replace')
+        if not stderr and self._stderr_path.exists():
+            stderr = self._stderr_path.read_text(encoding='utf-8', errors='replace')
         return stdout, stderr
 
     def get_coverage_file(self) -> Optional[Path]: