Code Kata: String Calculator in Flex
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The document describes a code kata exercise to develop a StringCalculator application using test-driven development. It provides requirements for the add() method of the StringCalculator class and outlines composing tests to verify each requirement fails initially and then developing the code to pass all tests. The requirements include handling empty strings, delimiters, optional delimiters, negative numbers, and ignoring large numbers. The process of writing tests before code and verifying all tests pass is demonstrated.
![Compose Test
there should be a StringCalculator
● add flexui:TestRunnerBase component to the test application
● add creationComplete handler to instantiate, init & run FlexUnitCore
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
xmlns:flexui="org.flexunit.flexui.*"
width="1200" height="900"
creationComplete="application1_creationCompleteHandler(event)">
<fx:Script>
<![CDATA[
import mx.events.FlexEvent;
import org.flexunit.runner.FlexUnitCore;
import suite.Suite;
protected function application1_creationCompleteHandler(event:FlexEvent):void{
var core:FlexUnitCore = new FlexUnitCore();
core.addListener(myRunnerBase);
core.run(suite.Suite);
}
]]>
</fx:Script>
<flexui:TestRunnerBase id="myRunnerBase" />
</s:WindowedApplication>](https://image.slidesharecdn.com/tddcodekata1-130118113727-phpapp01/85/Code-Kata-String-Calculator-in-Flex-5-320.jpg)
![Compose Test
there should be a StringCalculator
● Edit the Suite class
package suite{
import tests.Test;
[Suite]
[RunWith("org.flexunit.runners.Suite")]
public class Suite{
public var test:Test;
}
}](https://image.slidesharecdn.com/tddcodekata1-130118113727-phpapp01/85/Code-Kata-String-Calculator-in-Flex-6-320.jpg)
![Compose Test
there should be a StringCalculator
● Edit the Test class: add a passing test to get started
package tests{
import org.flexunit.Assert;
public class Test{
[Test]
public function Run_App_CompilesWithoutError():void{
var expected:Number = 3;
var actual:Number = Math.round(3.4999999);
Assert.assertEquals(expected, actual);
}
}
}](https://image.slidesharecdn.com/tddcodekata1-130118113727-phpapp01/85/Code-Kata-String-Calculator-in-Flex-7-320.jpg)
![Compose Test
throw exception for more than 2 inputs
● move StringCalculator to class and create in [Before]
● add test called
'Add_InputMoreThanTwoValues_ThrowsError'
● compose the test and it's assertion
● run StringCalclatorTestRunner
● see test fail](https://image.slidesharecdn.com/tddcodekata1-130118113727-phpapp01/85/Code-Kata-String-Calculator-in-Flex-15-320.jpg)
![Compose Test
return the sum of any number of inputs
● [Ignore] 'Add_InputMoreThanTwoValues_ThrowsError'
● add test called
'Add_InputMoreThanTwoValues_ReturnsSum'
● compose the test and it's assertion
● run StringCalclatorTestRunner
● see test fail](https://image.slidesharecdn.com/tddcodekata1-130118113727-phpapp01/85/Code-Kata-String-Calculator-in-Flex-22-320.jpg)
Code Kata: String Calculator in Flex
- 1. TDD Code Kata 1 StringCalculator
- 2. Ground Rules ● do not skip ahead ● no man left behind ● we will only get as far as the whole group gets by 12:50 to allow for discussion at the end ● when we're out of time, that's it ● next time, start from beginning again, not where we left off ● if participating, commit and obey the rules ● if observing, please do not assist or distract
- 3. Review Requirement There should be a StringCalculator application
- 4. Compose Test there should be a StringCalculator ● Launch FlashBuilder ● Create an application to run unit tests ● Create a new Flex Desktop Project called StringCalculatorTestRunner in your kata directory ● Add the FlexUnit swc's to to libs ● Add a class named Suite to a package named 'suite' ● Add a class named Test to a package named 'test'
- 5. Compose Test there should be a StringCalculator ● add flexui:TestRunnerBase component to the test application ● add creationComplete handler to instantiate, init & run FlexUnitCore <s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:flexui="org.flexunit.flexui.*" width="1200" height="900" creationComplete="application1_creationCompleteHandler(event)"> <fx:Script> <![CDATA[ import mx.events.FlexEvent; import org.flexunit.runner.FlexUnitCore; import suite.Suite; protected function application1_creationCompleteHandler(event:FlexEvent):void{ var core:FlexUnitCore = new FlexUnitCore(); core.addListener(myRunnerBase); core.run(suite.Suite); } ]]> </fx:Script> <flexui:TestRunnerBase id="myRunnerBase" /> </s:WindowedApplication>
- 6. Compose Test there should be a StringCalculator ● Edit the Suite class package suite{ import tests.Test; [Suite] [RunWith("org.flexunit.runners.Suite")] public class Suite{ public var test:Test; } }
- 7. Compose Test there should be a StringCalculator ● Edit the Test class: add a passing test to get started package tests{ import org.flexunit.Assert; public class Test{ [Test] public function Run_App_CompilesWithoutError():void{ var expected:Number = 3; var actual:Number = Math.round(3.4999999); Assert.assertEquals(expected, actual); } } }
- 8. Develop there should be a StringCalculator ● Create a directory on your computer for this kata project: kata/StringCalculator ● Create a new ActionScript web project called StringCalculator in your directory with default settings ● In Test App's Project Properties>Build Path>Source Path, add your StringCalculator project's src directory ● Run the test app, resolve any compiler issues ● See starter test pass
- 9. Review Requirement StringCalculator should have an add() function that: ● returns a Number ● accepts a String ● returns 0 for an empty string
- 10. Compose Test add() should exist and return 0 for empty string ● add a test called 'Add_InputEmptyString_ReturnsZero' ● instantiate the StringCalculator class ● call StringCalculator.add() ● Command+1 to 'create method add' ● run StringCalculatorTestRunner ● see test fail
- 11. Develop add() should exist and return 0 for empty string ● add a String parameter: add(numbers:String) ● add a return type of Number: add():Number ● add statements: var sum:Number; return sum;
- 12. Compose Test add() should exist and return 0 for empty string ● assert that 0 is returned for an empty string ● run StringCalclatorTestRunner ● see test fail
- 13. Develop add() should exist and return 0 for empty string ● add a condition where empty string returns 0 ● run StringCalclatorTestRunner ● see test pass Congratulations! Your first requirement is formally specified Your application's intent is formally documented Your application works as expected
- 14. Review Requirement The calculator's add function should: ● throw exception for more than 2 inputs ● return the value of 1 valid input ● return the sum of 2 valid inputs
- 15. Compose Test throw exception for more than 2 inputs ● move StringCalculator to class and create in [Before] ● add test called 'Add_InputMoreThanTwoValues_ThrowsError' ● compose the test and it's assertion ● run StringCalclatorTestRunner ● see test fail
- 16. Develop throw exception for more than 2 inputs ● add a condition where too many inputs throws an error ● run StringCalclatorTestRunner ● see all tests pass
- 17. Compose Test return the value of 1 valid input ● add test called 'Add_InputSingleValue_ReturnsInputValue' ● compose the test and it's assertion ● run StringCalclatorTestRunner ● see test fail
- 18. Develop return the value of 1 valid input ● add condition where single input value is returned ● run StringCalclatorTestRunner ● see all tests pass
- 19. Compose Test return the sum of 2 valid inputs ● add test called 'Add_InputTwoValues_ReturnsSum' ● compose the test and it's assertion ● run StringCalclatorTestRunner ● see test fail
- 20. Develop return the sum of 2 valid inputs ● add condition where sum of two inputs is returned ● run StringCalclatorTestRunner ● see all tests pass
- 21. Review Requirement The calculator's add function should return the sum of any number of inputs Here is a great example of how requirements change on us UnitTests help us to refactor code, safely and with confidence
- 22. Compose Test return the sum of any number of inputs ● [Ignore] 'Add_InputMoreThanTwoValues_ThrowsError' ● add test called 'Add_InputMoreThanTwoValues_ReturnsSum' ● compose the test and it's assertion ● run StringCalclatorTestRunner ● see test fail
- 23. Develop return the sum of any number of inputs ● remove condition where more than two inputs throws an error ● add condition and logic to add any number of inputs ● run StringCalclatorTestRunner ● see all tests pass
- 24. Review Requirement The calculator's add function should: ● accept the new line character 'n' as a delimeter ● 'n' and ',' are allowed in the same input: add('1n2,3')
- 25. Compose Test accept the new line character 'n' as a delimiter ● add test called 'Add_InputsDelimetedByNewLine_ReturnsSum' ● compose test and it's assertion ● run StringCalculatorTestRunner ● see test fail
- 26. Develop accept the new line character 'n' as a delimiter ● solve for requirement (eg. replace 'n' with ',') ● run StringCalculatorTestRunner ● see all tests pass
- 27. Review Requirement The calculator's add function should: ● optionally allow for different default delimiters via "//dn" ● example: add("//;n3;5;2n10;1) should return 21
- 28. Compose Test optionally allow for different default delimiters via "//dn" ● add test called 'Add_InputOptionalDelimiter_ReturnSum' ● compose test and it's assertion ● run StringCalculatorTestRunner ● see test fail
- 29. Develop optionally allow for different default delimiters via "//dn" ● solve for requirement ● run StringCalculatorTestRunner ● see all tests pass
- 30. Review Requirement The calculator's add function should: ● throw an exception when passed a negative number ● exception message is "negatives not allowed" ● include negative in message ● if multiple negatives, include them all in message
- 31. Compose Test throw an exception when passed negative number(s) ● add test called 'Add_InputNegativeNumbers_ThrowsException' ● compose test and it's assertion ● run StringCalculatorTestRunner ● see test fail
- 32. Develop throw an exception when passed negative number(s) ● solve for requirement ● run StringCalculatorTestRunner ● see all tests pass
- 33. Review Requirement The calculator's add function should: ● ignore numbers larger than 1000
- 34. Compose Test ignore numbers larger than 1000 ● add test called 'Add_InputValuesLargerThan1000_ReturnsSumIgnoringLargeNumbers' ● compose test and it's assertion ● run StringCalculatorTestRunner ● see test fail
- 35. Develop ignore numbers larger than 1000 ● solve for requirement ● run StringCalculatorTestRunner ● see all tests pass