Harry Percival

Harry Percival

Python and TDD enthusiast

  • @hjwp

London, England

Areas of Expertise:

  • Python
  • TDD
  • consulting
  • speaking
  • programming
  • training
  • writing
After an idyllic childhood spent playing with BASIC on French 8-bit computers like the Thomson T-07 whose keys go "boop" when you press them, Harry spent a few years being deeply unhappy as a management consultant. Soon he rediscovered his true geek nature, and was lucky enough to fall in with a bunch of XP fanatics, working on the pioneering but sadly defunct Resolver One spreadsheet. He now works at PythonAnywhere LLP, and spreads the gospel of TDD world-wide at talks, workshops and conferences, with all the passion and enthusiasm of a recent convert.

Test-Driven Development with Python Test-Driven Development with Python
by Harry Percival
June 2014
Print: $44.99
Ebook: $35.99

Harry blogs at:

Kent Beck on the limits of TDD

June 03 2014

For anyone that's been following the DHH / #isTDDDead controversy, or for anyone interested in what the limits of TDD are. Kent Beck (the godfather) had some really good reflections on what he was hoping to learn from the discussions: I'm puzzled by the limits of TDD--it works so well for algorithm-y, data-structure-y… read more

Book upgraded to Django 1.7!

April 02 2014

In a (futile) attempt to future-proof the book, I decided to upgrade it to Django 1.7. Here's how that went down. Overview Unsurprisingly, the biggest change was to do with migrations. Like any new change, my initial reaction was dislike, and I resented the new things, but I think overall it's a definite improvment. In brief,… read more

Webcast: Outside-in TDD and Unit Test Isolation with Python, Django and Selenium
June 05, 2014
This webcast will explore the methodology of outside-in test-driven development (TDD), as applied to a web application.

Webcast: TDD Web Development from Scratch
June 26, 2013
In this hands-on webcast presented by Harry Percival author of Test-Driven Development with Python, you will learn: how to use TDD to build a web application from the ground up, full functional testing using the Selenium browser automation tool, and ...