© Oscar Nierstrasz

ST — Smalltalk Basics

2.1

Change sets

> Make sure your changes are logged to a new change set

© Oscar Nierstrasz

ST — Smalltalk Basics

2.2

SUnit

© Oscar Nierstrasz

ST — Smalltalk Basics

2.3

Money

TestCase subclass: #MoneyTestinstanceVariableNames: 'chf2 chf8 chf10'classVariableNames: ''poolDictionaries: ''category: 'Money'

TestCase subclass: #MoneyTestinstanceVariableNames: 'chf2 chf8 chf10'classVariableNames: ''poolDictionaries: ''category: 'Money'

> We will implement the Money example in Smalltalk— First, we develop a test case for a single currency

NB: This is just a message sent to the TestCase class object (!)

© Oscar Nierstrasz

ST — Smalltalk Basics

2.4

SetUp

> We will need setters for the private Money state

MoneyTest>>setUpchf2 := Money new currency: 'CHF'; amount: 2.chf8 := Money new currency: 'CHF'; amount: 8.chf10 := Money new currency: 'CHF'; amount: 10.

MoneyTest>>setUpchf2 := Money new currency: 'CHF'; amount: 2.chf8 := Money new currency: 'CHF'; amount: 8.chf10 := Money new currency: 'CHF'; amount: 10.

© Oscar Nierstrasz

ST — Smalltalk Basics

2.5

MoneyTest>>testEquals

> Some obvious tests

MoneyTest>>testEqualsself assert: chf2 = chf2.self assert: chf2 = (Money new currency: 'CHF'; amount: 2).self assert: chf2 != chf8.

MoneyTest>>testEqualsself assert: chf2 = chf2.self assert: chf2 = (Money new currency: 'CHF'; amount: 2).self assert: chf2 != chf8.

© Oscar Nierstrasz

ST — Smalltalk Basics

2.6

Money

> We define Money as a subclass of Object, with getters and setters

Object subclass: #MoneyinstanceVariableNames: 'currency amount'classVariableNames: ''poolDictionaries: ''category: 'Money'

Object subclass: #MoneyinstanceVariableNames: 'currency amount'classVariableNames: ''poolDictionaries: ''category: 'Money'

Money>>currency: aStringcurrency := aString.

Money>>currency: aStringcurrency := aString.

Money>>currency^ currency

Money>>currency^ currency

© Oscar Nierstrasz

ST — Smalltalk Basics

2.7

Failing tests

© Oscar Nierstrasz

ST — Smalltalk Basics

2.8

Comparisons

Money>>= aMoney^ self currency = aMoney currencyand: [ self amount = aMoney amount ]

Money>>= aMoney^ self currency = aMoney currencyand: [ self amount = aMoney amount ]

Money>>!= aMoney^ (self = aMoney) not

Money>>!= aMoney^ (self = aMoney) not

© Oscar Nierstrasz

ST — Smalltalk Basics

2.9

Constructors

MoneyTest>>testEqualsself assert: chf2 = chf2.self assert: chf2 =

(Money currency: 'CHF' amount: 2).self assert: chf2 != chf8.

MoneyTest>>testEqualsself assert: chf2 = chf2.self assert: chf2 =

(Money currency: 'CHF' amount: 2).self assert: chf2 != chf8.

We need a constructor on the class side of Money

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

© Oscar Nierstrasz

ST — Smalltalk Basics

2.10

Class methods

NB: What “self” is referred to in the method body?

© Oscar Nierstrasz

ST — Smalltalk Basics

2.11

Addition

Money>>+ aMoney^ Money currency: self currency

amount: self amount + aMoney amount

Money>>+ aMoney^ Money currency: self currency

amount: self amount + aMoney amount

MoneyTest>>testAddself assert: chf2 + chf8 = chf10

MoneyTest>>testAddself assert: chf2 + chf8 = chf10

And so on …

© Oscar Nierstrasz

ST — Smalltalk Basics

2.12

Filing out your changes

> You can “file out” all your changes so they can be loaded into another image

© Oscar Nierstrasz

ST — Smalltalk Basics

2.13

License

> http://creativecommons.org/licenses/by-sa/2.5/

Attribution-ShareAlike 2.5You are free:• to copy, distribute, display, and perform the work• to make derivative works• to make commercial use of the work

Under the following conditions:

Attribution. You must attribute the work in the manner specified by the author or licensor.

Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one.

• For any reuse or distribution, you must make clear to others the license terms of this work.• Any of these conditions can be waived if you get permission from the copyright holder.

Your fair use and other rights are in no way affected by the above.

Attribution-ShareAlike 2.5You are free:• to copy, distribute, display, and perform the work• to make derivative works• to make commercial use of the work

Under the following conditions:

Attribution. You must attribute the work in the manner specified by the author or licensor.

Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one.

• For any reuse or distribution, you must make clear to others the license terms of this work.• Any of these conditions can be waived if you get permission from the copyright holder.

Your fair use and other rights are in no way affected by the above.