Bdd: Tdd and beyond the infinite

BEHAVIOUR DRIVEN DEVELOPMENT: TDD AND BEYOND THE INFINITE

Duct Tape Religion War

At the beginning…

end; // CellText := str; except // Gabriele non t'ha beccato, Gigi neppure, a chi toccherà? end; end;

while ((! found ) && ( pos < ( fileContent . Length - 6))) { byteData = new byte[6]; Array . Copy ( fileContent , pos , byteData , 0, 6); pos = pos + 6; str_byteData = enc . GetString ( byteData ); if ( str_byteData . Contains ( "s" )) { posE_byteData = str_byteData . IndexOf ( "s" ); pos = pos + ( posE_byteData - 6); Array . Copy ( fileContent , pos , byteData , 0, 6); pos = pos + 6; if ( byteData [0] == 0x73) // 's' { if ( byteData [1] == 0x74) // 't' { if ( byteData [2] == 0x72) // 'r' { if ( byteData [3] == 0x65) // 'e' { if ( byteData [4] == 0x61) // 'a' { if ( byteData [5] == 0x6D) // 'm' { found = true; break; } else { if ( byteData [5] == 0x73) { pos = pos - 1; } } }

function TfrmPreviewTrascr.DBToLinear(DB: Double): Double; begin //Result := Power(10, DB/20)*1; Result := Power(10, DB / 100) * 1; { TODO : trovare la relazione corretta } //LisyLabel4.Caption := Format('%.2f:%.2f', [DB, Result] ); end;

Kent Beck gave Tdd to programmers!

The Three Laws of TDD

The Three Laws of TDD 1 - You are not allowed to write any production code unless it is to make a failing unit test pass.

The Three Laws of TDD 1 - You are not allowed to write any production code unless it is to make a failing unit test pass. 2 - You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures.

The Three Laws of TDD 1 - You are not allowed to write any production code unless it is to make a failing unit test pass. 2 - You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures. 3 - You are not allowed to write any more production code than is sufficient to pass the one failing unit test.

TDD Cycle

Is that the end of our problems?

I’m a programmer, not a tester!

My code it’s difficult to test!

It’s a trivial, doesn’t need a test!

I’ve no time to make automatic tests!

It’s about specifications

Sapir-Whorf hypotesis “ there is a systematic relationship between the grammatical categories of the language a person speaks and how that person both understands the world and behaves in it.”

The Challenge

for ( var i = 1 ; i <= 100 ; i++){ var output = i + ": " ; if (i % 3 == 0 ) output += "fizz" ; if (i % 5 == 0 ) output += "buzz" ; console.log(output); } 48 sec

for ( var i = 1 ; i <= 100 ; i++){ var output = i + ": " ; if (i % 3 == 0 ) output += "fizz" ; if (i % 5 == 0 ) output += "buzz" ; console.log(output); } But it’s wrong!

puts ( 1 . .100 ). map { | n | '1' * n + ":#{n} " }. join . gsub ( /^(1{5})*:/,'Buzz').gsub(/^(1{3})*:/,'Fizz').gsub(/.*:|(z)d+/ , '1' ) WTF?!?!!

package biz . scalzo . tdd ; import junit . framework . Assert ; import org . junit . Test ; import biz . scalzo . tdd . Fizzbuzzer ; public class FizzbuzzTest { @Test public void testForOne (){ Assert . assertEquals ( "1" , new Fizzbuzzer (). count ( 1 )); } } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { return null ; } } Fizzbuzzer.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { return "1" ; } } Fizzbuzzer.java

@Test public void testForTwo (){ Assert . assertEquals ( "2" , new Fizzbuzzer (). count ( 2 )); } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { return Integer . toString ( i ); } } Fizzbuzzer.java

@Test public void testForThree (){ Assert . assertEquals ( "Fizz" , new Fizzbuzzer (). count ( 3 )); } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { if ( i == 3 ) return "Fizz" ; return Integer . toString ( i ); } } Fizzbuzzer.java

@Test public void testForFour (){ Assert . assertEquals ( "4" , new Fizzbuzzer (). count ( 4 )); } FizzbuzzTest.java

@Test public void testForFive (){ Assert . assertEquals ( "Buzz" , new Fizzbuzzer (). count ( 5 )); } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { if ( i == 3 ) return "Fizz" ; if ( i == 5 ) return "Buzz" ; return Integer . toString ( i ); } } Fizzbuzzer.java

@Test public void testForSix (){ Assert . assertEquals ( "Fizz" , new Fizzbuzzer (). count ( 6 )); } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { if ( i % 3 == 0 ) return "Fizz" ; if ( i == 5 ) return "Buzz" ; return Integer . toString ( i ); } } Fizzbuzzer.java

@Test public void testForSeven (){ Assert . assertEquals ( “7" , new Fizzbuzzer (). count ( 7 )); } FizzbuzzTest.java

@Test public void testForEight (){ Assert . assertEquals ( “8" , new Fizzbuzzer (). count ( 8 )); } FizzbuzzTest.java

@Test public void testForNine (){ Assert . assertEquals ( “Fizz" , new Fizzbuzzer (). count ( 9 )); } FizzbuzzTest.java

@Test public void testForTen (){ Assert . assertEquals ( "Buzz" , new Fizzbuzzer (). count ( 10 )); } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int i ) { if ( i % 3 == 0 ) return "Fizz" ; if ( i % 5 == 0 ) return "Buzz" ; return Integer . toString ( i ); } } Fizzbuzzer.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int number ) { if ( isMultipleOf ( number , 3 )) return "Fizz" ; if ( isMultipleOf ( number , 5 )) return "Buzz" ; return Integer . toString ( number ); } private boolean isMultipleOf ( int number , int multiple ) { return number % multiple == 0 ; } } Fizzbuzzer.java

@Test public void testForFifteen (){ Assert . assertEquals ( "FizzBuzz" , new Fizzbuzzer (). count ( 15 )); } FizzbuzzTest.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int number ) { if ( isMultipleOf ( number , 3 ) && isMultipleOf ( number , 5 )) return "FizzBuzz" ; if ( isMultipleOf ( number , 3 )) return "Fizz" ; if ( isMultipleOf ( number , 5 )) return "Buzz" ; return Integer . toString ( number ); } private boolean isMultipleOf ( int number , int multiple ) { return number % multiple == 0 ; } } Fizzbuzzer.java

package biz . scalzo . tdd ; public class Fizzbuzzer { public String count ( int number ) { String fizzOrBuzz = fizz ( number ) + buzz ( number ); return fizzOrBuzz . equals ( "" ) ? Integer . toString ( number ) : fizzOrBuzz ; } private boolean isMultipleOf ( int number , int multiple ) { return number % multiple == 0 ; } private String fizz ( int number ) { return isMultipleOf ( number , 3 ) ? "Fizz" : "" ; } private String buzz ( int number ) { return isMultipleOf ( number , 5 ) ? "Buzz" : "" ; } } Fizzbuzzer.java

Result

package biz . scalzo . tdd ; import junit . framework . Assert ; import org . junit . Test ; import biz . scalzo . tdd . Fizzbuzzer ; public class FizzbuzzTest { @Test public void testForOne (){ Assert . assertEquals ( "1" , new Fizzbuzzer (). count ( 1 )); } @Test public void testForTwo (){ Assert . assertEquals ( "2" , new Fizzbuzzer (). count ( 2 )); } @Test public void testForThree (){ Assert . assertEquals ( "Fizz" , new Fizzbuzzer (). count ( 3 )); } @Test public void testForFive (){ Assert . assertEquals ( "Buzz" , new Fizzbuzzer (). count ( 5 )); } @Test public void testForSix (){ Assert . assertEquals ( "Fizz" , new Fizzbuzzer (). count ( 6 )); } FizzbuzzTest.java

@Test public void testForSeven (){ Assert . assertEquals ( "7" , new Fizzbuzzer (). count ( 7 )); } @Test public void testForEight (){ Assert . assertEquals ( "8" , new Fizzbuzzer (). count ( 8 )); } @Test public void testForNine (){ Assert . assertEquals ( "Fizz" , new Fizzbuzzer (). count ( 9 )); } @Test public void testForTen (){ Assert . assertEquals ( "Buzz" , new Fizzbuzzer (). count ( 10 )); } @Test public void testForFifteen (){ Assert . assertEquals ( "FizzBuzz" , new Fizzbuzzer (). count ( 15 )); } } FizzbuzzTest.java

Bdd Way

Bdd Way Test method names should be sentences

package biz . scalzo . bdd ; import java . util . ArrayList ; import java . util . List ; import org . junit . Test ; import static org . hamcrest . MatcherAssert . assertThat ; import static org . hamcrest . Matchers .*; public class AFizzbuzzer { @Test public void shouldYellOneForOne () { assertThat ( new Fizzbuzzer (). count ( 1 ), is ( equalTo ( "1" ))); } } AFizzbuzzer.java

Bdd Way the class should do something

package biz . scalzo . bdd ; import java . util . ArrayList ; import java . util . List ; import org . junit . Test ; import static org . hamcrest . MatcherAssert . assertThat ; import static org . hamcrest . Matchers .*; public class AFizzbuzzer { @Test public void shouldYellOneForOne () { assertThat ( new Fizzbuzzer (). count ( 1 ), is ( equalTo ( "1" ))); } } AFizzbuzzer.java

@Test public void shouldYellTwoForTwo () { assertThat ( new Fizzbuzzer (). count ( 2 ), is ( equalTo ( "2" ))); } AFizzbuzzer.java

@Test public void shouldYellFizzForMultipleOfThree () { int [] fizzers = { 3 , 6 , 9 , 12 , 18 }; for ( int fizzer : fizzers ) { assertThat ( new Fizzbuzzer (). count ( fizzer ), is ( equalTo ( "Fizz" ))); } } AFizzbuzzer.java

@Test public void shouldYellBuzzForMultipleOfFive () { int [] buzzers = { 5 , 10 }; for ( int buzzer : buzzers ) { assertThat ( new Fizzbuzzer (). count ( buzzer ), is ( equalTo ( "Buzz" ))); } } AFizzbuzzer.java

@Test public void shouldYellFizzBuzzForMultipleOfThreeAndFive () { int [] fizzBuzzers = { 15 , 30 , 45 , 60 }; for ( int fizzBuzzer : fizzBuzzers ) { assertThat ( new Fizzbuzzer (). count ( fizzBuzzer ), is ( equalTo ( "FizzBuzz" ))); } } AFizzbuzzer.java

@Test public void shouldYellTheNumberForNotMultipleOfThreeOrFive () { for ( int plainNumber : plainNumbers ()) { assertThat ( new Fizzbuzzer (). count ( plainNumber ), is ( equalTo ( Integer . toString ( plainNumber )))); } } private List < Integer > plainNumbers () { List < Integer > numbers = new ArrayList < Integer >(); for ( int i = 1 ; i <= 100 ; i ++) numbers . add ( i ); for ( int i = 1 ; i < 35 ; i ++) numbers . remove ( new Integer ( i * 3 )); for ( int i = 1 ; i < 25 ; i ++) numbers . remove ( new Integer ( i * 5 )); return numbers ; } AFizzbuzzer.java

Fathers of Bdd

The Ruby Way to Bdd

$ :. unshift File . join ( File . dirname ( __FILE__ ), *% w [.. lib ]) require "fizzbuzzer" describe "Fizzbuzzer" do it "should yell one for one" do Fizzbuzzer . new . count ( 1 ). should == '1' end end fizzbuzzer_spec.rb

it "should yell two for two" do Fizzbuzzer . new . count ( 2 ). should == '2' end fizzbuzzer_spec.rb

it "should yell Fizz for three" do Fizzbuzzer . new . count ( 3 ). should == 'Fizz' end fizzbuzzer_spec.rb

it "should yell Fizz for multiple of three" do [ 3 , 6 , 9 , 12 ]. each do | number | Fizzbuzzer . new . count ( number ). should == 'Fizz' end end fizzbuzzer_spec.rb

it "should yell Buzz for multiple of five" do [ 5 , 10 ]. each do | number | Fizzbuzzer . new . count ( number ). should == 'Buzz' end end fizzbuzzer_spec.rb

it "should yell FizzBuzz for multiple of three and five" do [ 15 , 30 , 45 ]. each do | number | Fizzbuzzer . new . count ( number ). should == 'FizzBuzz' end end fizzbuzzer_spec.rb

it "should yell the number itself for non multiple of three or five" do ( 1 . .100 ). select { | n | n % 3 != 0 && n % 5 != 0 }. each do | number | Fizzbuzzer . new . count ( number ). should == number . to_s end end fizzbuzzer_spec.rb

Result

class Fixnum def fizzbuzzed ? "FizzBuzz" if self % 3 == 0 && self % 5 == 0 end def fizzed ? "Fizz" if self % 3 == 0 end def buzzed ? "Buzz" if self % 5 == 0 end end class Fizzbuzzer def count ( number ) number . fizzbuzzed ? || number . fizzed ? || number . buzzed ? || number . to_s end end fizzbuzzer.rb

describe "Fizzbuzzer" do it "should yell one for one" do Fizzbuzzer . new . count ( 1 ). should == '1' end it "should yell two for two" do Fizzbuzzer . new . count ( 2 ). should == '2' end it "should yell Fizz for multiple of three" do [ 3 , 6 , 9 , 12 ]. each do | number | Fizzbuzzer . new . count ( number ). should == 'Fizz' end end it "should yell Buzz for multiple of five" do [ 5 , 10 ]. each do | number | Fizzbuzzer . new . count ( number ). should == 'Buzz' end end it "should yell FizzBuzz for multiple of three and five" do [ 15 , 30 , 45 ]. each do | number | Fizzbuzzer . new . count ( number ). should == 'FizzBuzz' end end it "should yell the number itself for non multiple of three or five" do ( 1 . .100 ). select { | n | n % 3 != 0 && n % 5 != 0 }. each do | number | Fizzbuzzer . new . count ( number ). should == number . to_s end end end fizzbuzzer_spec.rb

output

Stories

As a [role] I want [feature] So that [benefit] Story

Scenario 1: Title Given [context] And [some more context]... When [event] Then [outcome] And [another outcome] Scenario Acceptance Criteria

Cucumber

Cucumber fizzbuzzer.feature fizzbuzzer_steps.rb

Feature : perfect fizzbuzzing As a inattentive counter I want an automatic Fizzbuzzer So that I can win Fizzbuzz Championsip fizzbuzzer.feature

Scenario : manage fizz numbers Given a Fizzbuzzer When I ask for a multiple of 3 Then Fizzbuzzer yells 'Fizz' fizzbuzzer.feature

require "fizzbuzzer" Given "a Fizzbuzzer" do @fizzbuzzer = Fizzbuzzer . new end When "I ask for a multiple of $m" do | m | @result = [ 1 , 2 ]. map { | base | @fizzbuzzer . count ( base * eval ( m ). to_i ) } end Then "Fizzbuzzer yells '$yell'" do | yell | @result . each do | result | result . should == yell end end fizzbuzzer_steps.rb

Scenario : manage buzz numbers Given a Fizzbuzzer When I ask for a multiple of 5 Then Fizzbuzzer yells 'Buzz' Scenario : manage fizzbuzz numbers Given a Fizzbuzzer When I ask for a multiple of 3 * 5 Then Fizzbuzzer yells 'FizzBuzz' fizzbuzzer.feature

Scenario : manage plain numbers Given a Fizzbuzzer When I ask for a plain number Then Fizzbuzzer yells the number itself fizzbuzzer.feature

When "I ask for a plain number" do @expected = ( 1 . .100 ). select { | n | n % 3 != 0 && n % 5 != 0 } @result = @expected . each do | number | @fizzbuzzer . count ( number ). to_i end end Then "Fizzbuzzer yells the number itself" do @result . should == @expected end fizzbuzzer_steps.rb

Scenario Outline : manage plain numbers Given a Fizzbuzzer When I ask for '<number>' Then Fizzbuzzer yells '<result>' Examples : | number | result | | 1 | 1 | | 2 | 2 | | 3 | Fizz | | 4 | 4 | | 5 | Buzz | | 6 | Fizz | fizzbuzzer.feature

neat, isn’t it?

Back to Java

Where it all started

jbehave manage_fizzbuzzer ManageFizzbuzzer.java ManageFizzbuzzerSteps.java

Feature : perfect fizzbuzzing As a inattentive counter I want an automatic Fizzbuzzer So that I can win Fizzbuzz Championsip Scenario : manage fizz numbers Given a Fizzbuzzer When I ask for a multiple of 3 Then Fizzbuzzer yells 'Fizz' Scenario : manage buzz numbers Given a Fizzbuzzer When I ask for a multiple of 5 Then Fizzbuzzer yells 'Buzz' Scenario : manage fizzbuzz numbers Given a Fizzbuzzer When I ask for a multiple of 15 Then Fizzbuzzer yells 'FizzBuzz' manage_fizzbuzzer

Scenario : manage plain numbers Given a Fizzbuzzer When I ask for a plain number Then Fizzbuzzer yells the number itself Scenario : manage plain numbers Given a Fizzbuzzer When I ask for '[number]' Then Fizzbuzzer yells '[yell]' Examples : | number | yell | | 1 | 1 | | 2 | 2 | | 3 | Fizz | | 4 | 4 | | 5 | Buzz | | 6 | Fizz | manage_fizzbuzzer

package biz . scalzo . jbehave ; import org . jbehave . scenario . Scenario ; public class ManageFizzbuzzer extends Scenario { public ManageFizzbuzzer () { super ( new ManageFizzbuzzerSteps ()); } } ManageFizzbuzzer.java

import biz . scalzo . bdd . Fizzbuzzer ; public class ManageFizzbuzzerSteps extends Steps { private Fizzbuzzer fizzbuzzer ; private List < String > results ; private List < String > expected ; private String result ; @BeforeScenario public void setUp () { expected = new ArrayList < String >(); results = new ArrayList < String >(); } ManageFizzbuzzerSteps.java

@ Given ( "a Fizzbuzzer" ) public void startFizzbuzzer () { fizzbuzzer = new Fizzbuzzer (); } @ When ( "I ask for a multiple of $divisor" ) public void askForMultipleOf ( int divisor ) { for ( int number = 1 ; number < 3 ; ++ number ) results . add ( fizzbuzzer . count ( number * divisor )); } @ Then ( "Fizzbuzzer yells '$yell'" ) public void checkYell ( String yell ) { for ( String result : results ) { assertThat ( result , is ( equalTo ( yell ))); } } ManageFizzbuzzerSteps.java

@ When ( "I ask for a plain number" ) public void askForPlainNumbers () { for ( int i = 1 ; i <= 100 ; i ++) if ( i % 3 != 0 && i % 5 != 0 ) expected . add ( Integer . toString ( i )); for ( String number : expected ) results . add ( fizzbuzzer . count ( Integer . parseInt ( number ))); } @ Then ( "Fizzbuzzer yells the number itself" ) public void yellsNumberItself () { for ( int i = 0 ; i < expected . size (); i ++) { assertThat ( results . get ( i ), is ( equalTo ( expected . get ( i )))); } } ManageFizzbuzzerSteps.java

@ When ( "I ask for '[number]'" ) public void askFor ( @ Named ( "number" ) int number ) { result = fizzbuzzer . count ( number ); } @ Then ( "Fizzbuzzer yells '[yell]'" ) public void checkResult ( @ Named ( "yell" ) String yell ) { assertThat ( result , is ( equalTo ( yell ))); } ManageFizzbuzzerSteps.java

Other Frameworks

ASSpec ActionScript 3
CppSpec C++
Spec- cpp C++
CSpec C
cfSpec ColdFusion
dSpec Delphi
easyb Groovy
EasySpec Groovy
tspec Groovy
GSpec Groovy
Concordion Java
GivWenZen Java
Instinct Java
JavaStubs Java
JBehave Java
JDave Java
beanSpec Java
JFXtras Test JavaFX
JSpec JavaScript
JSSpec JavaScript
Screw- unit JavaScript
Other Frameworks

NBehave .Net
NSpec .Net
NSpecify .Net
SpecUnit .Net
NUnit .Net
Specter .Net
StoryQ .Net
ObjectiveMatchy iPhone
PHPSpec PHP
Pyccuracy Python
Pyhistorian Python
PyCukes Python
Robot Framework Python
ScalaTest Scala
specs Scala
Other Frameworks

Conclusions?

Bdd is about specifications

Homework

http://github.com/coreyhaines/ practice_game_of_life

Feature: Evolving a living cell In order to create a functioning rules engine As a programmer of Conway's Game of Life I can evolve a single living cell Scenario: Living cell with 0 neighbors dies Given the following setup | . | . | . | | . | x | . | | . | . | . | When I evolve the board Then the center cell should be dead Scenario: Living cell with 1 neighbor dies Given the following setup | . | x | . | | . | x | . | | . | . | . | When I evolve the board Then the center cell should be dead Scenario: Living cell with 2 neighbors lives Given the following setup | . | x | . | | . | x | x | | . | . | . | When I evolve the board Then the center cell should be alive Scenario: Living cell with 3 neighbors lives Given the following setup | x | x | x | | . | x | . | | . | . | . | When I evolve the board Then the center cell should be alive

Start Bdd now!

? ? ? ? ? ?

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Bdd: Tdd and beyond the infinite

by giordano scalzo on Dec 03, 2009

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Bdd: Tdd and beyond the infinite — Presentation Transcript