Presented at C++ on Sea 2020, 15 July 2020
Links from this talk are at: https://github.com/claremacrae/talks/blob/main/Quickly_and_Effectively_Testing_Legacy_C++_Code_with_Approval_Tests.md#top
You've inherited some legacy code: it's valuable, but it doesn't have tests, and it wasn't designed to be testable, so you need to start refactoring. But you can't refactor safely until the code has tests, and you can't add tests without refactoring! How can you ever break out of this loop?
Whether Legacy code for you means "old code", "code without tests", or "code you wish to redesign for new features or unit-tests", this talk will enable you to become productive and work safely, quickly.
The simplicity, convenience, ease-of-use, power and flexibility of Llewellyn Falco's "Approval Tests" approach has long been proven in a dozen programming languages. And now all this is now available to C++ developers too!
Clare will present a small but surprisingly effective C++11 library for applying "Approval Tests" to cross-platform C++ code - for both legacy and green-field systems, and with a range of testing frameworks.
She will demonstrate its use in some real-world situations, including how to quickly lock down the behaviour of legacy code. She will show how to quickly achieve good test coverage, even for very large sets of inputs.
She will also show recent work applying Approval Tests to testing Graphical User Interfaces
Finally, she will describe some powerful techniques used in the implementation, that are useful beyond the field
Attendees will discover some quick, practical techniques to use for common challenges, such as testing GUI systems, and outputs containing dates and times, that can be applied very easily using Approval Tests.