Extract conversation history into thread-safe class with automatic trimming

[Copilot]

PrettyGeminiBot's conversation history was managed inline with direct list operations, lacking thread safety and automatic memory management.

Changes

New ConversationHistory class (embedded in mini_ema/bot/pretty_gemini_bot.py)

• Thread-safe operations via threading.Lock
• Automatic trimming on add_messages() prevents unbounded memory growth
• Reads configuration from PRETTY_GEMINI_BOT_HISTORY_LENGTH environment variable
• Hardcoded to 2 messages per round (user + assistant)
• Calculates max capacity once during initialization
• Always trims history (no conditional checks)

Updated PrettyGeminiBot (mini_ema/bot/pretty_gemini_bot.py)

• Replace direct list with ConversationHistory instance
• Simplified history management with no parameters needed
• Simplified message extraction to take last 2 messages directly

Testing Infrastructure

• Added pytest to project dependencies
• Added make test command to Makefile using pytest for test execution
• Created GitHub Actions workflow (.github/workflows/tests.yml) for automated testing
• Updated Copilot instructions with consolidated testing documentation

Usage

# Before
self.conversation_history = []
recent_history = self.conversation_history[-max_history_messages:]
self.conversation_history.append(msg1)
self.conversation_history.append(msg2)

# After
self.conversation_history = ConversationHistory()
recent_history = self.conversation_history.get_recent_messages()
self.conversation_history.add_messages([msg1, msg2])

History is automatically trimmed to max capacity (max_rounds * 2) on each write, preventing memory leaks in long-running conversations.

Testing

Run make test to execute all tests with pytest. Tests are also automatically run via GitHub Actions on push/PR to main branch.

Original prompt

把 Pretty gemini bot里面的对话历史管理单独抽离出来作为一个类，保证线程安全。同时历史只保留有用的最后N轮，超过的不要保留。只有数组[-index:]时候注意处理index为0的情况

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[Copilot]

Pull request overview

This PR refactors conversation history management in PrettyGeminiBot by extracting it into a dedicated ConversationHistory class with thread-safe operations and automatic memory management. It also establishes a testing infrastructure using pytest with CI/CD integration.

Key Changes:

• Thread-safe ConversationHistory class with automatic trimming prevents unbounded memory growth
• Simplified history management in PrettyGeminiBot using the new class interface
• Comprehensive test suite with pytest and automated CI/CD via GitHub Actions

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
mini_ema/bot/pretty_gemini_bot.py	Adds ConversationHistory class with thread-safe operations and refactors PrettyGeminiBot to use it
tests/test_conversation_history.py	Comprehensive unit tests for ConversationHistory including thread safety validation
pyproject.toml	Adds pytest dependency for testing infrastructure
Makefile	Adds make test command and updates help documentation
.github/workflows/tests.yml	New GitHub Actions workflow for automated test execution on push/PR
.github/copilot-instructions.md	Updates documentation with consolidated testing instructions