History of Email and Introduction to JUnit Testing in Java with Class 'Chapter' | Study notes Computer Science

For more info: http://www.mailmsg.com/history.htm!

CS1110 16 Sep 2008!

In 1968, the Defense Department hired Bolt Beranek and Newman (BBN)

of Boston to help develop the ARPANET, which later turned into the

internet. In 1971, Ray Tomlinson of BBN was given the task of figuring

out how to send files from one person to another. He created email with file

attachments. He selected @ as the separator between an email name and

location. Names for @ in other languages:!

Italian: chiocciolina != little snail!

French: petit escargot != little snail!

German: klammeraffe != spider monkey!

Dutch: api != short for apestaart"

! !(monkey's tail)!

Finnish: miau = cat tail!

Israeli: strudel = a pastry!

Danish: snabel != an "A" with a trunk!

Spanish: un arroba = a unit of about 25 pounds!

Norwegian: kanel-bolle!= spiral-shaped cinnamon cake!

TODAY:"

• Testing using JUnit.!

• Object: the superest class

of them all. pp 153-154.!

• Function toString.!

• Static variables and

methods. Sec. 1.5 (p. 47).!

/** Each instance describes a chapter in a book * */!

public class Chapter {!

private String title; // The title of the chapter!

private int number; // The number of chapter!

private Chapter previous; // previous chapter (null if none)!

/** Constructor: an instance with title t, chap n, previous chap c */!

public Chapter(String t, int n, Chapter c)!

{ title= t; number= n; previous= c; }!

/** = title of this chapter */!

public String getTitle() { return title; }!

/** = number of this chapter */!

public int getNumber() { return number; }!

/** = (name of) the previous chapter (null if none) */!

public Chapter getPrevious() { return previous; }!

Today, we use a

class Chapter. An

instance describes

a book. Here, we

have a constructor

and three getter

methods!

Download class

from course web

page.!

Testing --using Junit. Pages 385-388 (through Sec. 14.1.1)."

Bug: Error in a program.!

Testing: Process of analyzing, running program, looking for bugs.!

Test case: A set of input values, together with the expected output.!

Debugging: Process of finding a bug and removing it.!

Get in the habit of writing test cases for a method from the

specification of the method even before you write the method. !

To create a framework for testing in DrJava, select menu File

item new Junit test case…. At the prompt, put in the class

name ChapterTester. This creates a new class with that name.

Immediately save it —in the same directory as class Chapter.!

The class imports junit.framework.TestCase, which provides

some methods for testing.!

What test cases should we use to test this function?!

How many do we need?!

/** = a String that consists of the first letter of each word in s."

E.g. for s = “Juris Hartmanis”, the answer is “JH”.!

Precondition: s has one of the forms!

“first last” “first middle last”!

with one or more blanks between each pair of names. There

may be blanks at the beginning and end.!

public String initialsOf(String s) { … }!

/** A JUnit test case class.!

* Every method starting with the word "test" will be called when running!

* the test with JUnit. */!

public class ChapterTester extends TestCase {!

/** A test method.!

* (Replace "X" with a name describing the test. You may write as!

* many "testSomething" methods in this class as you wish, and each!

* one will be called when testing.) */!

public void testX() {!

}!assertEquals(x, y): !

test whether x equals y ; print an error message

and stop the method if they are not equal.!

x: expected value,"

y: actual value.!

Other methods listed on page 488.!

/** Test first constructor and getter methods getTitle,!

getNumber, and getPrevious */!

public void testFirstConstructor() {!

Chapter c1= new Chapter("one", 1, null);!

assertEquals("one”, c1.getTitle(), );!

assertEquals(1, c1.getNumber());!

assertEquals(null, c1.getPrevious());!

Every time you

click button Test

in DrJava, all

methods with a

name testXXX

will be called.!

one

test

case!

/** Test Setter methods setTitle, setNumber, and setPrevious */!

public void testSetters() {!

Chapter c1= new Chapter("one", 1, null);!

c1.setTitle("new title");!

c1.setNumber(18);!

Chapter c2= new Chapter("two", 2, null);!

c1.setPrevious(c2);!

assertEquals("new title", c1.getTitle());!

assertEquals(18, c1.getNumber());!

assertEquals(c2, c1.getPrevious());!

testMethods

to test getters

and setters!

Partial preview of the text

Download History of Email and Introduction to JUnit Testing in Java with Class 'Chapter' and more Study notes Computer Science in PDF only on Docsity!

For more info: http://www.mailmsg.com/history.htm 1

CS1110 16 Sep 2008

In 1968, the Defense Department hired Bolt Beranek and Newman (BBN) of Boston to help develop the ARPANET, which later turned into the internet. In 1971, Ray Tomlinson of BBN was given the task of figuring out how to send files from one person to another. He created email with file attachments. He selected @ as the separator between an email name and location. Names for @ in other languages: Italian: chiocciolina = little snail French: petit escargot = little snail German: klammeraffe = spider monkey Dutch: api = short for apestaart (monkey's tail) Finnish: miau = cat tail Israeli: strudel = a pastry Danish: snabel = an "A" with a trunk Spanish: un arroba = a unit of about 25 pounds Norwegian: kanel-bolle = spiral-shaped cinnamon cake

TODAY:

Testing using JUnit.
Object: the superest class of them all. pp 153-154.
Function toString.
Static variables and methods. Sec. 1.5 (p. 47). 2 /** Each instance describes a chapter in a book * / public class Chapter { private String title; // The title of the chapter private int number; // The number of chapter private Chapter previous; // previous chapter (null if none) /* Constructor: an instance with title t, chap n, previous chap c / public Chapter(String t, int n, Chapter c) { title= t; number= n; previous= c; } /* = title of this chapter / public String getTitle() { return title; } /* = number of this chapter / public int getNumber() { return number; } /* = (name of) the previous chapter (null if none) */ public Chapter getPrevious() { return previous; } } Today, we use a class Chapter. An instance describes a book. Here, we have a constructor and three getter methods Download class from course web page. 3

Testing --using Junit. Pages 385-388 (through Sec. 14.1.1).

Bug : Error in a program.

Testing : Process of analyzing, running program, looking for bugs.

Test case : A set of input values, together with the expected output.

Debugging : Process of finding a bug and removing it.

Get in the habit of writing test cases for a method from the

specification of the method even before you write the method.

To create a framework for testing in DrJava, select menu File

item new Junit test case…. At the prompt, put in the class

name ChapterTester. This creates a new class with that name.

Immediately save it —in the same directory as class Chapter.

The class imports junit.framework.TestCase , which provides

some methods for testing. 4

What test cases should we use to test this function?

How many do we need?

/** = a String that consists of the first letter of each word in s.

E.g. for s = “Juris Hartmanis”, the answer is “JH”.

Precondition: s has one of the forms

“first last” “first middle last”

with one or more blanks between each pair of names. There

may be blanks at the beginning and end.

public String initialsOf(String s) { … }

5 /** A JUnit test case class.

Every method starting with the word "test" will be called when running
the test with JUnit. / public class ChapterTester extends TestCase { /* A test method.
(Replace "X" with a name describing the test. You may write as
many "testSomething" methods in this class as you wish, and each
one will be called when testing.) */ public void testX() { }

} assertEquals(x, y):

test whether x equals y ; print an error message

and stop the method if they are not equal.

x: expected value,

y: actual value.

Other methods listed on page 488. 6

/** Test first constructor and getter methods getTitle, getNumber, and getPrevious */ public void testFirstConstructor() { Chapter c1= new Chapter("one", 1, null); assertEquals("one”, c1.getTitle(), ); assertEquals(1, c1.getNumber()); assertEquals(null, c1.getPrevious()); } Every time you click button Test in DrJava, all methods with a name testXXX will be called.

one

test

case

/** Test Setter methods setTitle, setNumber, and setPrevious */ public void testSetters() { Chapter c1= new Chapter("one", 1, null ); c1.setTitle("new title"); c1.setNumber(18); Chapter c2= new Chapter("two", 2, null ); c1.setPrevious(c2); assertEquals("new title", c1.getTitle()); assertEquals(18, c1.getNumber()); assertEquals(c2, c1.getPrevious()); }

testMethods

to test getters

and setters

Class Object: The superest class of them all

See 1/2-page section 4.3.1 on page 154.

The reason for this will become clear later.

You need this information to do assignment A2.

Every class that does not extend another one automatically

extends class Object.

public class C { … }

is equivalent to

public class C extends Object { …}

Class Object: The superest class of them all

Bill

name B. Clinton^ Patient

address New York

owes $250.

See 1/2-page section 4.3.1 on

page 154.

Bill

name B. Clinton Patient

address New York

owes $250.

equals(Object)

toString()

this is really this

Object

Because it is always there, to

avoid clutter, we don’t

generally draw the partition

for superclass Object

Method toString()

Bill

name B. Clinton Patient

address New York

owes

toString()

equals(Object)

toString()

Object

Convention: c.toString() returns a representation of folder c, giving info about the values in its fields. Put following method in Patient. /** = representation of this Patient */ public String toString() { return name + “ ” + address + “ ” + owes; }

In appropriate places, the

expression c automatically

does c.toString()

Example of toString in another class

/** An instance represents a point (x, y) in the plane */

public class Point {

private int x; // the x-coordinate

private int y; // the y-coordinate

/** Constructor: An instance for point (xx, yy) */

public Point( int xx, int yy) {

/** = a representation of this point in form “(x, y)” */

public String toString() {

return ;

Getter and setter methods are not given on this slide

Function toString should give the values in the

fields in a format that makes sense for the class.

Example: “(3, 5)” Fill these in 11

A static field does not appear in each folder.

It appears in the file drawer, by itself, on a piece of paper.

There is only ONE copy of it.

public class Chapter { private String title; // title of chapter private static int numberChaps= 0; // no. of Chapter objects created } Reference static variable using Chapter.numberChaps

a

title “peace”^ Chapter

a

title “truth”^ Chapter

numberChaps 2

File drawer for class Chapter

Use a static variable when you want to maintain

information about all (or some) folders.

Make a method static when it does not refer

to any of the fields or methods of the folder.

public class Chapter { private int number; // Number of chapter private static int numberOfChapters= 0; /** = “This chapter has a lower chapter number than Chapter c”. Precondition: c is not null. / public boolean isLowerThan(Chapter c) { return number < c.number; } } /* = “b’s chapter number is lower than c’s chapter number”. Precondition: b and c are not null. */ public static boolean isLower(Chapter b, Chapter c) { return b.number < c.number; }

History of Email and Introduction to JUnit Testing in Java with Class 'Chapter', Study notes of Computer Science

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Partial preview of the text

Download History of Email and Introduction to JUnit Testing in Java with Class 'Chapter' and more Study notes Computer Science in PDF only on Docsity!

CS1110 16 Sep 2008

TODAY:

Testing --using Junit. Pages 385-388 (through Sec. 14.1.1).

Bug : Error in a program.

Testing : Process of analyzing, running program, looking for bugs.

Test case : A set of input values, together with the expected output.

Debugging : Process of finding a bug and removing it.

Get in the habit of writing test cases for a method from the

specification of the method even before you write the method.

To create a framework for testing in DrJava, select menu File

item new Junit test case…. At the prompt, put in the class

name ChapterTester. This creates a new class with that name.

Immediately save it —in the same directory as class Chapter.

The class imports junit.framework.TestCase , which provides

some methods for testing. 4

What test cases should we use to test this function?

How many do we need?

/** = a String that consists of the first letter of each word in s.

E.g. for s = “Juris Hartmanis”, the answer is “JH”.

Precondition: s has one of the forms

“first last” “first middle last”

with one or more blanks between each pair of names. There

may be blanks at the beginning and end.

public String initialsOf(String s) { … }

} assertEquals(x, y):

test whether x equals y ; print an error message

and stop the method if they are not equal.

x: expected value,

y: actual value.

Other methods listed on page 488. 6

one

test

case

testMethods

to test getters

and setters

Class Object: The superest class of them all

See 1/2-page section 4.3.1 on page 154.

The reason for this will become clear later.

You need this information to do assignment A2.

Every class that does not extend another one automatically

extends class Object.

public class C { … }

is equivalent to

public class C extends Object { …}

Class Object: The superest class of them all

Bill

name B. Clinton^ Patient

address New York

owes $250.

See 1/2-page section 4.3.1 on

page 154.

Bill

name B. Clinton Patient

address New York

owes $250.

equals(Object)

toString()

this is really this

Object

Because it is always there, to

avoid clutter, we don’t

generally draw the partition

for superclass Object

Method toString()

Bill

name B. Clinton Patient

address New York

owes

toString()

equals(Object)

toString()

Object

In appropriate places, the

expression c automatically

does c.toString()

TODAY:

Testing --using Junit. Pages 385-388 (through Sec. 14.1.1).

/** = a String that consists of the first letter of each word in s.

x: expected value,

A static field does not appear in each folder.