Show HN: FizzBee – Formal Model based autonomous testing

---

Hand-written test cases don’t scale. As systems grow more stateful and concurrent, it becomes impossible to anticipate every edge case. Most testing completely misses concurrency issues.

With Model-based testing (MBT), instead of writing tests, you define how your system should behave. FizzBee then generates and runs lots and lots of scenarios, automatically checking your implementation against the model.

It’s like property-based testing for stateful, concurrent systems.

---

1. Define the model — Describe valid operations and rules for your system in FizzBee’s python-like state machine language.
2. Generate scenarios — FizzBee autonomously explores sequences of actions and interleavings.
3. Refinement mapping — Connect the code to the design - defining how the code implements the design by implementing a adapter interface.
4. Run Tests — FizzBee Test Runner tests your system extensively including concurrent behavior and reports any violations.

---

• Concurrency-Aware
  FizzBee systematically explores interleavings, catching subtle race conditions that other MBT tools miss.

• Clean Source Code
  No intrusive tracing libraries or logging calls; test logic is fully isolated from your code.

• Incremental Testing
  Test as you build. Unimplemented features can be marked and ignored, so new code is validated immediately. This enables true test-driven development, without having to write tests.

• Truly Autonomous
  Unlike AI-written tests, FizzBee requires no manual review of generated cases. Tests are deterministic, reproducible, and mathematically rigorous — with no fragile edits when your code changes.

• Replayable Failures
  Every bug comes with a minimal, reproducible trace for fast debugging.

---

✅ Catch concurrency bugs early
✅ Test incrementally during development (true TDD for stateful systems)
✅ Keep source code clean and uncluttered
✅ Validate against formal models, not scattered assertions
✅ Build confidence faster in complex, distributed software

---

• Distributed databases and storage systems
• APIs and microservices with evolving state
• Concurrent services where order of operations matters
• Any stateful system too complex for hand-written test suites

---

FizzBee MBT lets you focus on what the system should do, not how to manually test it.
Define the rules once. Let FizzBee do the rest.

👉 Get Started with Model-Based Testing