Introduction to Test Driven Development

INTRODUCTION TO TEST DRIVEN DEVELOPMENTPresented by Sarah Dutkiewicz

[email protected]

AGENDA

• Test Driven Development – What does this mean?

• Gathering Requirements

• Gherkin

• Tools for TDD in the Workplace

WHAT IS TEST DRIVEN DEVELOPMENT?

TEST DRIVEN DEVELOPMENT

• Define {something} first through a test

• Write the code to pass the test

• Verify that the test succeeds

• Improve upon the code and keep the test passing

Write the test

Write the code to pass the

test

Improve the code while keeping the test passing

RED-GREEN-REFACTOR

EXAMPLE – RUBY KOANS

EXAMPLE – RUBY KOANS

TDD CONCEPT - ASSERTIONS

• Verify whether a certain condition has been met

• Asserts come in many forms:• (Not) Equal• Contains / Any• Is a Type• Is an Instance of a Type• Is (Not) Null• Is (True/False)

• Design Guideline – One assert per test

TDD CONCEPT – ARRANGE/ACT/ASSERT

• Pattern for arranging a test

1. Arrange all preconditions and inputs.

2. Act on the object or method.

3. Assert that the results have occurred.

TEST-DRIVEN – TYPES OF TESTSTests, Tests, and More Tests… Oh My!

TYPES OF TESTS

• Unit Tests

• Integration Tests

• End-to-End Tests

• Exploratory Testing

UNIT TESTS

• Focus on a class or a method

• Tests the smallest unit possible

• Typically tests simple objects; does not test things such as:• Database communication• Network communication• File system manipulation

INTEGRATION TESTS

• Tests functions, “does things”

• Tests interactions with the outside world, include:• Database communication• Network communication• File system manipulation

• Focused integration tests isolate the testing to one interaction at a time

• Integration tests should run on their own, with a little help from 2 fundamental units:• Setup – run at the beginning of the test to set up

the test environment• Tear-down – run at the end of the test or upon

error to clean up the test environment

END-TO-END TESTS• The most brittle of tests –

dependent on the big picture

• Verifies that the unit tests and integration tests are working like they should

• Start at the beginning and go through the whole process

• Includes:• Acceptance testing• Functional testing

EXPLORATORY TESTING

• Not an automated process; manual testing

• Sometimes better to go this route rather than end-to-end tests – depending on the design and architecture of your application

• EXPLORE!• Discovery• Investigation• Learning

MORE *-DRIVEN DEVELOPMENTRelated philosophies and methodologies

OTHER RELATED *-DRIVEN DEVELOPMENT

• Behavior Driven Development

• Acceptance Test Driven Development

• Specification by Example

ACCEPTANCE TEST DRIVEN DEVELOPMENT CYCLE

Discuss the requirements

Distill the tests in a

friendly format

Develop the code (and hook the code to the

tests)

Demo the code

ATDD AND THE TDD CYCLE

Discuss the requirements

Distill the tests in a

friendly format

Develop the code (and hook the code to the

tests)

Demo the code

RED

GREEN

REFACTOR

GREEN

GATHERING REQUIREMENTSThe Importance of TDD & ATDD for the UX Realm and an Intro to Gherkin

• Conducted by all who are involved:• Product owners• Business analysts• Developers• QA

• Requirements are explicitly spelled out.• Include use cases.• Include required behaviors or designs.

DISCUSS

GHERKIN

• Common language for gathering requirements

• Written in “plain English” following a particular cadence

• Can then be hooked up to various programming languages and testing tools

• Serves as guidelines for automated tests as well as project documentation

GHERKIN COMPONENTS

• Features

• Scenarios & Scenario Outlines

• Backgrounds

• Steps

• Multiline Arguments

• Tags

FEATURES

• Define a feature of an application

• Starts with the Feature keyword and contains a few lines to define the feature

Example:

Feature: Short, concise, descriptive text of the goal

In order to do something

As someone related to this system

I want to gain something out of this

* Features are stored in a *.feature file

FEATURE EXAMPLE

Feature: Checking out books

In order to read eBooks on my eBook reader,

As a library patron,

I want to check out eBooks.

SCENARIOS

• Possibilities of situations (scenarios) that apply to a feature

• Scenarios are included in *.feature files with their relevant feature

• Created with one or more steps

SCENARIO EXAMPLE

Scenario: Checking out a book

Given the library collection has the book I want to check out

When I check out the book

Then the library collection’s available count is reduced by 1

STEPS

• Given a certain given condition

• When a certain behavior happens

• Then a certain outcome is expected

• Additional keywords include But and And

• Given a certain given condition

• And another given condition

• When a certain behavior happens

• Then a certain outcome is expected

SCENARIO OUTLINES

• Scenario Outlines eliminate the need for copying and pasting like scenarios and collapsing values into variables.

• Rather than starting with Scenario, it starts with Scenario Outline.

• Variables (placeholders) are denoted with names sandwiched in greater-than and less-than symbols.

SCENARIO OUTLINE EXAMPLE

Scenario Outline: Checking book checkout expiration

Given a checkout period of <checkout_period> days

When I open the book at day <open>

Then the book should expire in <left> days

Examples:

| checkout_period | open | left |

| 7 | 2 | 5 |

| 14 | 10 | 2 |

| 21 | 18 | 3 |

MULTILINE ARGUMENTS

• Tables

Example:

Scenario:

Given the following accounts exist:

|name |email |account_type|

| Laura |[email protected] | Admin |

| Sarah |[email protected] | Admin |

| Kevin | [email protected] | User |

MULTILINE ARGUMENTS

• Large paragraph of text

Example:

Scenario:

Given a description search with:

" " " It was the best of times It was the worst of times " " "

BACKGROUNDS

• Backgrounds setup the environment for all scenarios in a feature file.

• Starts with the Background keyword and is typically made up of Given, And, and But clauses

• Runs before individual scenario setup routines

BACKGROUND EXAMPLE

Feature: Checkout eMaterials

Background:

Given a customer named “Sarah Dutkiewicz“

And a library card numbered “12345678901”

And a checkout queue of books:

| title | author |

| Hop on Pop | Dr. Seuss |

| Harold and the Purple Crayon | Crockett Johnson |

| Shark Tales: How I Turned $1,000 into a Billion Dollar Business | Barbara Corcoran|

TAGS

• Used for grouping like tests, scenarios, and/or features together

• Starts with a @, followed by the tag name

Examples:

@UI @accounting @security

• Many test runners support tags and allow collections of tests to be run by tag

TOOLS FOR TDD IN THE WORKPLACE

GHERKIN LANGUAGE RESOURCES AND GENERAL TDD

RESOURCES• Behat – Writing Features – Gherkin Language

• The Art of Agile Development: Test-Driven Development

• Test first != TDD

• Driving Development with Tests: ATDD and TDD

• Let’s Explore – Exploratory Testing

.NET TDD RESOURCES• SpecFlow – Behavior Driven Development,

Acceptance Test Driven Development, Specification by Example; includes support for Silverlight, Windows Phone, and Mono

• TestDriven.Net – Visual Studio integration for unit tests

• WatiN – Web Application Testing in .NET

• TestStack.White – UI automation testing

• Telerik Test Studio

• Nunit

• MbUnit

• MSTest

• NCover

• TypeMock

JAVASCRIPT TDD RESOURCES

• QUnit

• Jasmine

• Zombie.js

• Mocha

• Tutti

• JSTestDriver

• jsUnity

• CasperJS

RUBY TDD RESOURCES

• Cucumber – behavior driven development

• Watir – Web Application Testing in Ruby

• Ruby Koans – learn Ruby via testing

• Rspec – primary Ruby testing tool

PHP TDD RESOURCES

• Behat – behavior driven development

• Mink – web acceptance testing

• PHPUnit

• SimpleTest

• Phpt

• Gouette – headless browser, web scraper

JAVA TDD RESOURCES

• JUnit

• Watij – Web Application Testing in Java

• AppPerfect Java Unit Test

ADDITIONAL *DD RESOURCES

• Sahi – JavaScript browser controller

• Selenium – supports C#, Java, Perl, PHP, Python, Ruby

• Fitnesse – supports multiple languages

• Windmill – supports Python, JavaScript, Ruby

• Canoo WebTest – supports Python, JavaScript

• TSQLUnit – TDD for Transact-SQL

• TST – the T-SQL Test Tool

CONTACT INFORMATION

Sarah Dutkiewicz

Cleveland Tech Consulting, LLC

[email protected]

Twitter: @sadukie

Blog: http://codinggeekette.com