A Second Look at Unit Testing

A Second Look

at Unit Testing@RoyOsherove

royo@bouvet.no

• Unit Of Work• Setup Methods

• Constrained vs. Unconstrained Isolation

Frameworks• Principles of Good Isolation Frameworks

• Faking Deep Legacy is OK• Six Influence Forces

• Beautiful Builds

Bottleneck Ninja Test Review Lion Build Bear

Unit

Of W

orkProduction

Code

Unit Of Work

Return Value/Exceptio

nNoticeable

State Change 3rd Party call

Public API

Test

Production Code

Unit Of Work

Return Value/Exceptio

n

Public API

Assert Test

Production Code

Unit Of Work

Noticeable State Change

Test

Public API

Asse

rt

Production Code

Unit Of Work

3rd Party call

Test

Public API As

sert

3rd Party

Unit Of Work

Production Code

Unit Of Work

3rd Party call

Test

Public API As

sert

3rd Party

Unit Of Work

Mock

Nam

ing

by U

nit

Of W

ork

UnitOfWork_Input_ExpectedOutput

UnitOfWork_LogicalAction_ExpectedChangeInBehavior

UnitOfWork_ActionOrInput_ExepectedCallToThirdParty

Nam

ing

by U

nit

Of W

ork

Addition_PositiveNumbers_ReturnsSum()

Addition_WhenCalled_ResetsTheNextSum() Addition_NegativeNumber

s_CallsLogger()

Setu

p Me

thod

s

Isola

tion

Fram

ewor

ks Constrained vs. Unconstrained

Good

bye

Rhin

oMoc

ks Hello FakeItEasy,

NSubstitute

Isola

tion

fram

ewor

ks Fu

ture

s

Usability Readability Good Errors Simplicity Robust future proof tests Less over specification

Non strict Recursive Fakes

Rspec style is ok

Assert multiple results on

same unit of work

LEGACY CODEFaking Deep

System Internals is OKExample - SilverUnit

Cross Cutting Fakes

Old code

Old code FakeNewcode

CROSS CUTTING FAKES

Impacting Change

6 in

fluen

ce

forc

es

Personal Ability Motivation Social Ability Motivation Environmental Ability Motivation

Anot

her b

ook?

Tool

s

Pex – yes Moles (ms fakes) – NO JustMock - Maybe Nuget – YES Chocolatey – YES

TeamCity – YES FinalBuilder – YES Ruby and Rake – Maybe Amazon AWS agent hosting –

YES Git for very small commits -

YES

Build and Delivery

Build Patterns

Build

Scr

ipt

Inje

ctio

n Allow version aware builds Build scripts are part

of source control Build configurations on

the CI server are dumb triggers

Extra

ct S

crip

t

Extract Script

Build Chain Triggers

Triggered by checkin

Triggered by end of previous

Manual

Manual

Build Chaining

Slow Builds

Do X

Do X + Y

Do X + Y + Z

Do X + y + Z + N

Cumulative, Fast Builds

Do X

Do Y

Do Z

Do N

How Fast?

Extract Script Shipping Skeleton Fill in the blanks Cumulative Builds Build Waves Location Agnostic

BeautifulBuilds.com

(wtf how many books?)

Cour

ses I

’m

Doin

g

Beautiful builds TDD with JS TDD with Ruby Art of Unit Testing in .NET from scratch roy@osherove.com

Norway & Sweden Osherove.com for info

A sh

ort s

ong?

This is a test line

It looks like you’re

doing just fine

It’s time for a

song of mine

It’s late in the evening

It’s l

ate

in th

e ev

enin

g

I’m wondering what words to say It’s so hard to breath

here The customer’s face is gray

And then he asks me

Is the product

alright?

And I say

“yes, we deploy it all tonight”

I check in the changes

I check in the changes

The code doesn’t even

compile

I wish I was home now

Instead I fake a big smile

And when they ask me

Is the code alright?

I say

“yes, it seems to

compile tonight’

I feel horribleBecause I see

The sadness in

their eyes

When they find out

That the product

Doesn’t even have

log files

This thing is

doomed

It’s time to go

home nowAnd I’ve got an aching

head

So I lock my computer

And pray that tomorrow

I’m dead

When my wife asks me

“Do you feel

alright?”

I say “yes. Let’s watch game of thrones tonight”

I fee

l mise

rabl

e Because I’ll guess The madness in their

talk

When they find out that tomorrow I don’t plan to come to work And write my CV

Than

k yo

u!

Beautiful builds TDD with JS TDD with Ruby Art of Unit Testing in .NET from scratch roy@osherove.com

@RoyOsherove Norway & Sweden