Nizar Selander is a software engineer and consultant in Sweden. He builds tools for test-driven development with coding agents, including TDD Guard and its successor Probity.[1][2]
Start with Probity →
Career
Selander’s earlier TDD Guard used test-runner reporting and agent hooks to guide the same red–green–refactor cycle. Its repository remains available, while directing new projects toward Probity. His professional site describes a consulting practice centered on software engineering, test-driven development and agentic workflows.[1][4]
Contributions
Probity integrates with a coding agent’s hooks to check file writes and shell commands. Configured rules can match commands or file content, require an earlier command, or use a model to validate an action in light of the session’s recent history. A blocked action returns an explanation and a suggested next step.[3]
Ideas
Its built-in TDD rule asks for an observed failing test before production code, a minimal implementation and refactoring after tests pass. Those steps constrain the workflow, but they do not guarantee good tests or a well-designed program. The documentation distinguishes token-free pattern checks from model-based checks that add calls to the agent’s existing provider.[3]
Tools, writing & talks
Tools
Start here
Probity
github.comConfigurable checks on agent file writes and commands, including a TDD workflow rule.
Read the rule examples and agent-specific hook setup, then try one rule in a small project. It needs a compatible coding agent and Node environment; model-validated rules consume additional provider usage.
- TDD Guardgithub.com
The earlier agent integration for enforcing test-first development steps.
Creator and repository owner[2][4]Original source