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


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.



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 aperson 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}\n" }.join. gsub(/^(1{5})*:/,'\0Buzz').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



public String count(int i) { return "1"; }

}

Fizzbuzzer.java

@Testpublic void testForTwo(){ Assert.assertEquals("2", new Fizzbuzzer().count(2));}

FizzbuzzTest.java



public String count(int i) { return Integer.toString(i); }

}

Fizzbuzzer.java

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

FizzbuzzTest.java



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



public String count(int i) { if (i == 3) return "Fizz"; if (i == 5) return "Buzz";


}

Fizzbuzzer.java

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

FizzbuzzTest.java



public String count(int i) { if (i % 3 == 0) return "Fizz"; if (i == 5) return "Buzz";


}

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



public String count(int i) { if (i % 3 == 0) return "Fizz"; if (i % 5 == 0) return "Buzz";


}

Fizzbuzzer.java



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



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



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' endend

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 endend

class Fizzbuzzer def count(number) number.fizzbuzzed? || number.fizzed? || number.buzzed? || number.to_s endend

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 endend

fizzbuzzer_spec.rb

output

Stories

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

Story

Scenario 1: TitleGiven [context] And [some more context]...When [event]Then [outcome] And [another outcome]

Scenario Acceptance Criteria

Cucumber

Cucumber

fizzbuzzer.featurefizzbuzzer_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.newend

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 endend

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 == @expectedend

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_fizzbuzzerManageFizzbuzzer.javaManageFizzbuzzerSteps.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))); } }


@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)))); } }


@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))); }


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!

? ? ????

bdd: tdd and beyond the infinite

Technology