Skip to content

Testing and UB

Photo of
Hosted By
Phil N. and 4 others
Testing and UB


This month we welcome visiting speaker, Clare Macrae, as well as our own Tom Waldron

A big thanks to Cloudflare, who are hosting us at short notice after Skills Matter went into administration). They're based near Waterloo Station, so very central. It's a great venue - and they have free snacks and drinks!
If we behave well enough that they let us, we'll probably meet there often from now.

To submit a talk idea for future events please visit


19:00 Intro and News - Phil Nash

19:05 "Undefined Behaviour by default" - Tom Waldron

A quick splash around in the sub-genre of embedded C++ for microcontrollers, which relies heavily on implementation defined and undefined magic as standard.

19:45 Break

20:00 "C++ Testing Techniques, Tips and Tricks"

An assortment of practical techniques to make it easier to write effective automated tests of C++ code, both old and new.

Clare will share some approaches for easier handling of commonly troublesome testing scenarios. This is a brand new talk, that is independent of test frameworks, and even covers a little for those creating Qt desktop applications.


About the speakers

Clare is an independent consultant, helping teams streamline their work with legacy and hard-to-test C++ and Qt code. She has worked in software development for over 30 years, and in C++ for 20 years.

Since 2017, she has used her spare time to work remotely with Llewellyn Falco on ApprovalTests.cpp, to radically simplify testing of legacy code. She has enjoyed this so much that she recently went independent, to focus even more on helping others to work more easily with legacy code.

Clare was until recently a Principal Scientific Software Engineer at Cambridge Crystallographic Data Centre, which releases structural data and powerful software for scientific education, research, and streamlining the design and manufacture of new medicines.

From 2016 to 2018, she lead the team that replaced their 30 year old database format and Fortran code. She then returned to C++ and Qt, working on the popular 3D crystal structure visualisation program Mercury, which she was the original author of.

When not thinking about supporting teams to streamline development, testing and releases, she spends time with family and friends, and enjoys the Raspberry Pi, folk music and cinema.


Tom is a Senior Embedded Design Engineer for ROLI, bass guitar player for Nova Neon, cycling enthusiast and occasional capoeirista.

He uses C++ with efficiency in mind, running on constrained systems, making use of compile-time trickery and abuse of compiler settings. His favourite tools are Visual Studio Code and a soldering iron.

Belvedere Road · London