Why I Started Using This Tool

When I first had to write unit tests for embedded C code at work, I hit a wall almost immediately. My functions used pointers — for output parameters, buffers, structs — and I had no idea how to feed them into a test framework. TBrun kept coming up as the tool my team used, but every tutorial I found assumed you already knew what you were doing. I needed a real beginner's guide, so I built one myself.

What It Does

TBrun (Test Bench Run) is a unit testing framework designed specifically for C code, popular in safety-critical and embedded software development. It lets you define test cases through a structured interface and automatically generates the scaffolding to call your function, pass in controlled inputs, and verify the outputs — including functions that work through pointers.

Think of it like a flight simulator for your C functions: you control the inputs, the environment is isolated, and you check whether the outputs match what you expected — all without touching the real system.

  • Pointer argument support — TBrun lets you define input and output pointer values directly in the test case editor, so you don't have to manually wire up memory addresses
  • Auto-generated test harness — it writes the boilerplate main(), includes, and assertions for you, so you focus on what the test means, not how to plumb it together
  • Pass/fail reporting — after a test run you get a clear result per case, which matters when you're tracking coverage for a safety standard like ISO 26262 or DO-178C

My Honest Pros & Cons

✅ What I Love

  • Once you understand the input/output table structure, writing a pointer test case takes under five minutes
  • The generated code is readable — you can open it and actually understand what TBrun built on your behalf
  • Works well with stubbing: if your function calls another function internally, TBrun can replace it with a controlled stub so your test stays isolated

❌ What Could Be Better

  • The learning curve for pointer arguments specifically is steep — the UI doesn't make it obvious whether you're setting the pointer value or the value at the address, and beginners get burned by this constantly
  • Documentation is thin for edge cases like double pointers or pointer-to-struct with nested members
  • Error messages when a test case is misconfigured can be cryptic, especially for someone new to the tool

Pricing: Is It Worth It?

TBrun is a commercial tool sold as part of the LDRA tool suite, so there's no free tier for professional use. Licensing is typically sold per seat and negotiated through LDRA directly — expect enterprise pricing that reflects its target market of safety-critical development teams.

If you're a student or just learning, ask your university or employer whether they have an existing LDRA licence — many aerospace, automotive, and defence organisations already do.

My take: If your team is already in a safety-critical domain and needs traceability and coverage metrics, TBrun earns its cost quickly. For a personal or hobbyist project, it's overkill.

Final Verdict

TBrun is a solid, professional-grade tool for unit testing C code — and once you crack the pointer argument syntax, it genuinely speeds up test writing. Use it if you're working in embedded or safety-critical C development and your team already has access to the LDRA suite. Skip it if you're building a side project or learning unit testing for the first time — start with something like Unity or CMock instead, get comfortable with the concepts, and come back to TBrun when the job demands it.