Testing Legacy C++ Code effectively with Approval Tests

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 workshop will enable you to become productive and work safely, quickly.

In this hands-on workshop, you will learn not just how to use Approval Tests to start testing legacy code, but how to create effective, maintainable, expressive tests, even on large systems.

Prerequisites

• Some prior experience of programming in C++
• Zoom with a microphone and camera
• AnyDesk software installed, to log in to a shared virtual machine on Amazon's infrastructure (subject to change)

Syllabus/Topics:

• Testing functional/pure code
• Testing with Approval Tests
• Testing non-functional/non-pure code
• Testing code in hard-to-test scenarios (of time)

Attendees will learn how to:

• Break the cycle of can't refactor/no tests
• Break up an existing application to add tests
• Approval Tests
• Write first Approval Test
  • Chose suitable tools for visualising program output (pick effective Reporter)
  • Deal with non-stable output
  • Use Approval Tests effectively, for highly maintainable tests