Custom thread pool executor that does not block interpreter shutdown, adapted from CPython's ThreadPoolExecutor. It allows graceful shutdown without waiting for pending futures, making it suitable for long-running applications where the main thread may exit before all tasks complete. The implementation is self-contained and can be extracted for any Python project needing a non-blocking thread pool.

Base class for all HTTP requests to the ycmd server. Provides asynchronous execution via a thread pool, HMAC-based request signing for security, automatic retry with user confirmation for extra configuration files, and structured error handling. The pattern is generic enough to be reused for any client-server communication requiring authentication and async responses.

Composable filter chain for suppressing diagnostics by level (error, warning, info) or by regular expression pattern. Filters can be combined with AND/OR logic and applied per filetype. This pattern is reusable for any tool that needs to filter messages (e.g., linters, compilers) based on user-defined criteria.

Provides MockVimModule, VimBuffer, VimWindow, and other utilities to simulate Vim's Python API for unit testing. Includes regex-based eval mocking, buffer/window management, and sign placement simulation. This is a reusable pattern for any Vim plugin developer needing to test Python code that interacts with Vim internals.