tdd dojo - test driven development coding dojo

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Test Driven Development DojoA safe way to be introduced to a powerful way of programming !!Roberto Bettazzoni


About me

Agile Coach eXtreme Programming Trainer !>30 years of coding (and still proudly counting) [email protected] linkedin.com/in/robertobettazzoni @bettazzoni

Roberto Bettazzoni

mailto:[email protected]?subject=

http://www.linkedin.com/in/robertobettazzoni


T.D.D. Coder Dojo Agenda

• TDD in a very small nutshell • TDD Sempai demo • For each Kata (35 min.)

‣ Choose the Kata ‣ execute ‣ break (5 min.) ‣ StandUp

道場型

agile42 | We advise, train and coach companies building software | www.agile42.com | Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License agile42 | We advise, train and coach companies building software www.agile42.com | All rights reserved. Copyright © 2007 - 2010.

Test Driven Development


Test-Driven Development as Formula

TDD = ( Test First

+ Unit Testing

+ Refactoring )

* Baby Steps


Test First


Test First Programming

!

“Write a failing automated test before changing any code.”

!

Kent Beck, Extreme Programming Explained 2nd Ed. 2004


Unit Test


unit test

Method to verify isolated units of code


unit test

user

code

Acceptance Criteria test

Functional test

Unit test


unit test



unit test

assert condition


unit test



Test Isolation

B

D

C

A


Test Isolation

Run 4 tests: A, B, C, D

B

D

C

A


Test Isolation

B

D

C

A


Test Isolation

Run 3 tests: A, B, D

B

D

A


Test Isolation

Run 3 tests: D, A, B

B

D

A


unit test library

test()


unit test library

setUp() - test() - tearDown()


unit test



unit test - What is a unit of code?

Classes Methods Functions

Blocks of code


Code Isolation (or Unit Isolation)

B

D

C

A


Code Refactoring


Refactoring

Changing existing code without changing its external behavior


Refactoring

Make your code better without changing its external behavior


Three Principles to Write Good Code

1. Find good names 2. Remove duplications 3. There is no third principle


Refactoring. The Sensei Words

Any fool can write code that a computer can understand.

Good programmers write code that humans can understand

Martin Fowler, Refactoring: Improving the Design of Existing Code, 1999 pag. 15


Baby Steps


Baby steps.

… proceed iteratively in baby steps — the shortest step that can be

appreciated in the right direction

Kent Beck, Extreme Programming Explained 2nd Ed. 2004


The TDD process

Unit tests suite pass

Add a unit testAdd a unit test

Write a unit test

Write the code

Refactor the code

Refactor the tests

Unit test pass

Unit test fails


The TDD process from the Functional Tests

Add a functional testRun the test & check failure

Run all functional tests see all pass

!

Refactor the

Design


Welcome to the coding dojo


dojo

道場 (place of the way)


kata

型 (form)


Dojo Kun (the dojo rules)

At the Dojo one can’t discuss a form without code, and one can’t show code without tests. It is a design training place, where it is acknowledged that “the code is the design” and that code without tests simply doesn’t exist. Emily Bache, The Coding Dojo Handbook, 2012 (translated from Christophe Thibaut, Laurent Bossavit’s blog, 2005)

You are here to practice, not to build something No output is required, neither logging or tracing activities Every aspect of the kata (design, UI …) is in your hands


Sempai Demo

Let’s start the Sempai TDD Demo


Coding Dojo retrospective


TDD ALL CODE IS GUILTY

UNTIL PROVEN INNOCENT


Food for thoughts

tdd dojo - test driven development coding dojo

Software

coach companies

unported license agile42

test firstagile42

test driven developmentagile42

baby steps agile42

failing automated test

unit testing refactoring

powerful way of programming