feat: add comprehensive unit tests for pipeline stages (#1701)

* feat: add comprehensive unit tests for pipeline stages

* fix: deps install in ci

* ci: use venv

* ci: run run_tests.sh

* fix: resolve circular import issues in pipeline tests

Update all test files to use lazy imports via importlib.import_module()
to avoid circular dependency errors. Fix mock_conversation fixture to
properly mock list.copy() method.

Changes:
- Use lazy import pattern in all test files
- Fix conftest.py fixture for conversation messages
- Add integration test file for full import tests
- Update documentation with known issues and workarounds

Tests now successfully avoid circular import errors while maintaining
full test coverage of pipeline stages.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* docs: add comprehensive testing summary

Document implementation details, challenges, solutions, and future
improvements for the pipeline unit test suite.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: rewrite unit tests to test actual pipeline stage code

Rewrote unit tests to properly test real stage implementations instead of
mock logic:

- Test actual BanSessionCheckStage with 7 test cases (100% coverage)
- Test actual RateLimit stage with 3 test cases (70% coverage)
- Test actual PipelineManager with 5 test cases
- Use lazy imports via import_module to avoid circular dependencies
- Import pipelinemgr first to ensure proper stage registration
- Use Query.model_construct() to bypass Pydantic validation in tests
- Remove obsolete pure unit tests that didn't test real code
- All 20 tests passing with 48% overall pipeline coverage

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* test: add unit tests for GroupRespondRuleCheckStage

Added comprehensive unit tests for resprule stage:

- Test person message skips rule check
- Test group message with no matching rules (INTERRUPT)
- Test group message with matching rule (CONTINUE)
- Test AtBotRule removes At component correctly
- Test AtBotRule when no At component present

Coverage: 100% on resprule.py and atbot.py
All 25 tests passing with 51% overall pipeline coverage

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: restructure tests to tests/unit_tests/pipeline

Reorganized test directory structure to support multiple test categories:

- Move tests/pipeline → tests/unit_tests/pipeline
- Rename .github/workflows/pipeline-tests.yml → run-tests.yml
- Update run_tests.sh to run all unit tests (not just pipeline)
- Update workflow to trigger on all pkg/** and tests/** changes
- Coverage now tracks entire pkg/ module instead of just pipeline

This structure allows for easy addition of more unit tests for other
modules in the future.

All 25 tests passing with 21% overall pkg coverage.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* ci: upload codecov report

* ci: codecov file

* ci: coverage.xml

---------

Co-authored-by: Claude <noreply@anthropic.com>

tests/unit_tests/pipeline/conftest.py

@@ -0,0 +1,251 @@
+"""
+Shared test fixtures and configuration
+
+This file provides infrastructure for all pipeline tests, including:
+- Mock object factories
+- Test fixtures
+- Common test helper functions
+"""
+
+from __future__ import annotations
+
+import pytest
+from unittest.mock import AsyncMock, MagicMock, Mock
+from typing import Any
+
+import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
+import langbot_plugin.api.entities.builtin.platform.message as platform_message
+import langbot_plugin.api.entities.builtin.platform.events as platform_events
+import langbot_plugin.api.entities.builtin.provider.session as provider_session
+import langbot_plugin.api.entities.builtin.provider.message as provider_message
+
+from pkg.pipeline import entities as pipeline_entities
+
+
+class MockApplication:
+    """Mock Application object providing all basic dependencies needed by stages"""
+
+    def __init__(self):
+        self.logger = self._create_mock_logger()
+        self.sess_mgr = self._create_mock_session_manager()
+        self.model_mgr = self._create_mock_model_manager()
+        self.tool_mgr = self._create_mock_tool_manager()
+        self.plugin_connector = self._create_mock_plugin_connector()
+        self.persistence_mgr = self._create_mock_persistence_manager()
+        self.query_pool = self._create_mock_query_pool()
+        self.instance_config = self._create_mock_instance_config()
+        self.task_mgr = self._create_mock_task_manager()
+
+    def _create_mock_logger(self):
+        logger = Mock()
+        logger.debug = Mock()
+        logger.info = Mock()
+        logger.error = Mock()
+        logger.warning = Mock()
+        return logger
+
+    def _create_mock_session_manager(self):
+        sess_mgr = AsyncMock()
+        sess_mgr.get_session = AsyncMock()
+        sess_mgr.get_conversation = AsyncMock()
+        return sess_mgr
+
+    def _create_mock_model_manager(self):
+        model_mgr = AsyncMock()
+        model_mgr.get_model_by_uuid = AsyncMock()
+        return model_mgr
+
+    def _create_mock_tool_manager(self):
+        tool_mgr = AsyncMock()
+        tool_mgr.get_all_tools = AsyncMock(return_value=[])
+        return tool_mgr
+
+    def _create_mock_plugin_connector(self):
+        plugin_connector = AsyncMock()
+        plugin_connector.emit_event = AsyncMock()
+        return plugin_connector
+
+    def _create_mock_persistence_manager(self):
+        persistence_mgr = AsyncMock()
+        persistence_mgr.execute_async = AsyncMock()
+        return persistence_mgr
+
+    def _create_mock_query_pool(self):
+        query_pool = Mock()
+        query_pool.cached_queries = {}
+        query_pool.queries = []
+        query_pool.condition = AsyncMock()
+        return query_pool
+
+    def _create_mock_instance_config(self):
+        instance_config = Mock()
+        instance_config.data = {
+            'command': {'prefix': ['/', '!'], 'enable': True},
+            'concurrency': {'pipeline': 10},
+        }
+        return instance_config
+
+    def _create_mock_task_manager(self):
+        task_mgr = Mock()
+        task_mgr.create_task = Mock()
+        return task_mgr
+
+
+@pytest.fixture
+def mock_app():
+    """Provides Mock Application instance"""
+    return MockApplication()
+
+
+@pytest.fixture
+def mock_session():
+    """Provides Mock Session object"""
+    session = Mock()
+    session.launcher_type = provider_session.LauncherTypes.PERSON
+    session.launcher_id = 12345
+    session._semaphore = AsyncMock()
+    session._semaphore.locked = Mock(return_value=False)
+    session._semaphore.acquire = AsyncMock()
+    session._semaphore.release = AsyncMock()
+    return session
+
+
+@pytest.fixture
+def mock_conversation():
+    """Provides Mock Conversation object"""
+    conversation = Mock()
+    conversation.uuid = 'test-conversation-uuid'
+
+    # Create mock prompt with copy method
+    mock_prompt = Mock()
+    mock_prompt.messages = []
+    mock_prompt.copy = Mock(return_value=Mock(messages=[]))
+    conversation.prompt = mock_prompt
+
+    # Create mock messages list with copy method
+    mock_messages = Mock()
+    mock_messages.copy = Mock(return_value=[])
+    conversation.messages = mock_messages
+
+    return conversation
+
+
+@pytest.fixture
+def mock_model():
+    """Provides Mock Model object"""
+    model = Mock()
+    model.model_entity = Mock()
+    model.model_entity.uuid = 'test-model-uuid'
+    model.model_entity.abilities = ['func_call', 'vision']
+    return model
+
+
+@pytest.fixture
+def mock_adapter():
+    """Provides Mock Adapter object"""
+    adapter = AsyncMock()
+    adapter.is_stream_output_supported = AsyncMock(return_value=False)
+    adapter.reply_message = AsyncMock()
+    adapter.reply_message_chunk = AsyncMock()
+    return adapter
+
+
+@pytest.fixture
+def sample_message_chain():
+    """Provides sample message chain"""
+    return platform_message.MessageChain(
+        [
+            platform_message.Plain(text='Hello, this is a test message'),
+        ]
+    )
+
+
+@pytest.fixture
+def sample_message_event(sample_message_chain):
+    """Provides sample message event"""
+    event = Mock()
+    event.sender = Mock()
+    event.sender.id = 12345
+    event.time = 1609459200  # 2021-01-01 00:00:00
+    return event
+
+
+@pytest.fixture
+def sample_query(sample_message_chain, sample_message_event, mock_adapter):
+    """Provides sample Query object - using model_construct to bypass validation"""
+    import langbot_plugin.api.entities.builtin.pipeline.query as pipeline_query
+
+    # Use model_construct to bypass Pydantic validation for test purposes
+    query = pipeline_query.Query.model_construct(
+        query_id='test-query-id',
+        launcher_type=provider_session.LauncherTypes.PERSON,
+        launcher_id=12345,
+        sender_id=12345,
+        message_chain=sample_message_chain,
+        message_event=sample_message_event,
+        adapter=mock_adapter,
+        pipeline_uuid='test-pipeline-uuid',
+        bot_uuid='test-bot-uuid',
+        pipeline_config={
+            'ai': {
+                'runner': {'runner': 'local-agent'},
+                'local-agent': {'model': 'test-model-uuid', 'prompt': 'test-prompt'},
+            },
+            'output': {'misc': {'at-sender': False, 'quote-origin': False}},
+            'trigger': {'misc': {'combine-quote-message': False}},
+        },
+        session=None,
+        prompt=None,
+        messages=[],
+        user_message=None,
+        use_funcs=[],
+        use_llm_model_uuid=None,
+        variables={},
+        resp_messages=[],
+        resp_message_chain=None,
+        current_stage_name=None
+    )
+    return query
+
+
+@pytest.fixture
+def sample_pipeline_config():
+    """Provides sample pipeline configuration"""
+    return {
+        'ai': {
+            'runner': {'runner': 'local-agent'},
+            'local-agent': {'model': 'test-model-uuid', 'prompt': 'test-prompt'},
+        },
+        'output': {'misc': {'at-sender': False, 'quote-origin': False}},
+        'trigger': {'misc': {'combine-quote-message': False}},
+        'ratelimit': {'enable': True, 'algo': 'fixwin', 'window': 60, 'limit': 10},
+    }
+
+
+def create_stage_result(
+    result_type: pipeline_entities.ResultType,
+    query: pipeline_query.Query,
+    user_notice: str = '',
+    console_notice: str = '',
+    debug_notice: str = '',
+    error_notice: str = '',
+) -> pipeline_entities.StageProcessResult:
+    """Helper function to create stage process result"""
+    return pipeline_entities.StageProcessResult(
+        result_type=result_type,
+        new_query=query,
+        user_notice=user_notice,
+        console_notice=console_notice,
+        debug_notice=debug_notice,
+        error_notice=error_notice,
+    )
+
+
+def assert_result_continue(result: pipeline_entities.StageProcessResult):
+    """Assert result is CONTINUE type"""
+    assert result.result_type == pipeline_entities.ResultType.CONTINUE
+
+
+def assert_result_interrupt(result: pipeline_entities.StageProcessResult):
+    """Assert result is INTERRUPT type"""
+    assert result.result_type == pipeline_entities.ResultType.INTERRUPT