Mocks, Fakes and Stubs
Mocks, Fakes and Stubs
and other techniques in Test Driven Development, illustrated with Code Katas
About the Book
If you're interested in improving your practice at programming in general, and Test Driven Development in particular, I'd suggest doing code katas is a good way to learn. There's a host of programmers around the world using code katas to hone their skills and learn from one another, in a coding dojo, at a code retreat, in a pair on a lunchbreak, or just by themselves. This book uses Code Katas to illustrate some modern coding techniques, so you can learn about, and practice them.
A code kata is a simple coding problem that may take a little effort to solve the first time, but the point is you don't only do it once. Start over from scratch and try it again, but think more carefully about how you're solving it. Can you work in small steps, refactoring often, and keep your design simple and clean? Can you write a good suite of automated tests that support your development and provide good regression protection for future maintenance work? The challenge in a Code Kata is to solve the problem well, and to demonstrate good practices in how you reach your solution. If you're using Code Katas like this, you'll find you build up a repertoire of katas that you know well, and can use to polish your coding technique.
Code Katas are also useful when you're trying out something new - a tool, technique or coding environment. Keep one variable the same - the problem to solve - and see how your coding experience, design, and tests are affected by the new element. It's this way of using Code Katas that is the focus of this book. I'm assuming you are familiar with each code kata, and can use it to show you a new technique.
In this book I'll show you examples including, but not limited to, Mocks Fakes and Stubs. I'll also discuss techniques like London School TDD, Outside-In development, and Approval testing. I'll begin each topic with a discussion of the theory, and follow it up with some code listings and sample tests. My aim is that it'll be a little like pair programming with someone experienced in the technique, who can explain what they mean both in theory and example, and give you some commentary about when you might choose to use it. You'll definitely be expected to put in some work yourself, learning the Code Katas, and trying the techniques out for yourself. It'll certainly be more fun if you can get a group together and start a Coding Dojo.
My first book, "The Coding Dojo Handbook", is full of practical advice about how to set up this kind of a space for learning. While I was working on that book, I found myself writing long passages about particular techniques, and how you could learn about them using some of the code katas listed in the catalogue in that book. In the end, I decided that material didn't belong in "The Coding Dojo Handbook", and that it would be better to start a new book.
The techniques in "Mocks, Fakes and Stubs" are all useful to practice in a Coding Dojo environment, but not exclusively. I've included examples taken from a range of programming languages, including Java, Python, C++ and C#. You can do a Code Kata in pretty much any language you feel like, and you'll find and starting code is available in many popular languages on my Github page. All the code katas used in this book are listed in the Kata Catalogue from "The Coding Dojo Handbook".
- How to Read This Book
- Two kinds of practice
Unit Testing Basics
- What is an automated unit test?
- Unit Testing explained with a simple example
- Test Case Design
Test-Driving an Algorithm
- Stress Testing
- Example with a Stub
- Example with a Fake
- Example with a Mock
- Example with a Test Spy
- Using an isolation framework for Mocks and Spies
- Example with a Dummy object
- Why use test doubles?
- Using Meta-Programming to insert test doubles
- Double-Loop TDD
The London School of TDD
- Classic vs London School
- Designing Outside-In
- Outside-In, With London School TDD
- “Tell, Don’t Ask” Object Oriented Design
- Mocks used badly
- Outside-In example (not written yet)
- Tell, Don’t Ask example (not written yet)
- London School TDD illustrated (not written yet)
- Minesweeper example
- The Golden Master
- Tools for Approval Testing
- Legacy Code
Other Techniques that I havn’t decided on yet
- Further Reading
The Leanpub 60-day 100% Happiness Guarantee
Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
80% Royalties. Earn $16 on a $20 book.
We pay 80% royalties. That's not a typo: you earn $16 on a $20 sale. If we sell 5000 non-refunded copies of your book or course for $20, you'll earn $80,000.
(Yes, some authors have already earned much more than that on Leanpub.)
In fact, authors have earnedover $12 millionwriting, publishing and selling on Leanpub.
Learn more about writing on Leanpub
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers) and EPUB (for phones, tablets and Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.