A Simple Intro To

TDD

quick question

s to start!

had a client who knew what he

needed?

question 1

been in a project with no change in

requirements?

question 2

predicted every problem 3 months

in advance?

question 3

Agile Context of Testing1

respond to change!

A

B

A

BC

change

risk

reduce the risk!

reduce the risk!

use the agile iterative cycle

reduce the risk!

test continuously

fast feedback

know what works at any given

moment

Types of Tests2

Functional TestsExamples

Story TestsPrototypesSimulations

Unit TestsComponent Tests

Exploratoy TestingScenarios

Usability TestingUATA/B

Performance & Load TestingSecurity Testing

“ility Testing”

Automated & Manual

Automated

Manual

Tools

Q2

Q3

Q1

Q4

Business Facing

Technology Facing

Supp

ortin

g th

e Te

am Critique Product

Functional TestsExamples

Story TestsPrototypesSimulations

Unit TestsComponent Tests

Exploratoy TestingScenarios

Usability TestingUATA/B

Performance & Load TestingSecurity Testing

“ility Testing”

Automated & Manual

Automated

Manual

Tools

Q2

Q3

Q1

Q4

Business Facing

Technology Facing

Supp

ortin

g th

e Te

am Critique Product

Coding

Unit TestingProgram Unit Design

Physical Design

Logical Design

User Requirements

Integration Testing

System Testing

AcceptanceTesting

Verifies

Verifies

Verifies

Verifies

hardexpensiveslow

easycheapfastmore

lessUI

Integration

Unit

What Is A Unit Test?3

Unit Tests

•Tests a single unit of code (typically a method)•Tests the unit of code in ISOLATION•Tests that the code behaves as expected

Unit Tests

• It’s still code•Code that tests code

•Exercise SUT, check behaviour

•Concepts: Test Class, Test Method

Test Structure

AAA

ARRANGE

ACT

ASSERT

Test Structure

ARRANGE

ACT

ASSERT

Unit Tests

•Should be fast (< 10 ms)•Should be consistent (same result always)•Should run in memory (no db, file access)•Should run in any order (no dependencies on other tests)

Impacts

•Fast Feedback•Cleaner design •Code and componente decoupling•Confidence•Executable documentation, with usage samples•Reduce regression

TDD vs. Unit Testing4

unit testing is not TDD

TDDis

unit testing (in a particular order)

TDD in three steps

TDD isdifferent approach

to coding

Demo5

https://github.com/MiguelAlho/TddCalculator

References6

Books

•Pragmatic Unit Testing In C# with Nunit•Growing software guided by tests•The art of unit Testing•Testable Javascript•Quality Code•Xunit Patterns