RobDWaller A Developer


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I am a software developer and manager with nearly a decade and a half of experience. I also built Twitter's largest anti-bot app.

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Test to Break Principles

Home > Talks > Test to Break Principles Author: Rob Waller Tags: tests, QA, unit tests, test to work, test to break

Talk Abstract

There are two types of tests a developer can write, ‘test to work’ and ‘test to break’. Both are essential to robust development, but many developers only use the former and not the latter. This talk explains why ‘test to break’ principles are essential to ensure robust application development.

Talk Description

The talk aims to highlight the importance of testing, why developers must spend more of their time testing, how testing generates more robust applications and why testing makes developers’ lives easier.

The talk is based around a live coding demo.

The talk will:

  • Explain the difference between tests that prove an application works and tests which aim to break the application logic.
  • Highlight how test to break principles force developers to introduce logic to handle unexpected behaviour.
  • Show how test to break principles result in more robust applications as developers write code that can only be used in one way.
  • Encourage developers to apply test to break principles to all types of tests, including manual tests.


This talk is based on a blog post found on my personal site:

There is also a GitHub library which will form the basis of the demo: