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BizSpark SF Lightning Talk: "Refactoring and Test-Driven Development" by Mathias Brandewinder

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Presentation from November 2011 BizSparkSF Meetup entitled "Tools, Tools and More Tools!" http://www.bizsparksf.com/events/34653282/

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What is TDD? (answer: Test-Driven Development) and why you should care Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 1
Once upon a Time Design Implement Test Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 2
Stay buggy, my friends! Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 3
Start with the tests! If I needed to Add 1 + 1 Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 4
If I needed to Add 1 + 1 [Test] public void When_Adding_One_Plus_One_Answer_Should_Be_Two() { // Assert var expectedResult = 2; Assert.That(actualResult, Is.EqualTo(expectedResult)); } I would expect the answer to be 2 Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 5
If I needed to Add 1 + 1 [Test] public void When_Adding_One_Plus_One_Answer_Should_Be_Two() { // Act var actualResult = calculator.Add(1, 1); // Assert var expectedResult = 2; Assert.That(actualResult, Is.EqualTo(expectedResult)); } I would need a Calculator Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 6
If I needed to Add 1 + 1 [Test] public void When_Adding_One_Plus_One_Answer_Should_Be_Two() { // Arrange var calculator = new Calculator(); // Act var actualResult = calculator.Add(1, 1); // Assert var expectedResult = 2; Assert.That(actualResult, Is.EqualTo(expectedResult)); } I would need some code Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 7
If I needed to Add 1 + 1 Does the code work? Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 8
Testing frameworks MsTest Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 9
Its not about Testing 損 Its about writing Code that works, now 損 Imagine you had implemented the feature 損 then implement it 損 Rinse & Repeat until you have no test to write Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 10
Why should you care? Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 11
The dreaded L word 息 www.dilbert.com Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 12
To me, legacy code is simply code without tests. Michael Feathers, Working Effectively with Legacy Code Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 13
Did I break everything? Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 14
Tests: a Vise holding your code steady Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 15
A good test is 損 Fast 損 Focused 損 Replicable 損 Automated Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 16
Refactoring: improve the code structure, without changing its external behavior. Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 17
Red, Green, Refactor 損 Red: write a little test that doesnt work 損 Green: make the test work quickly 損 Refactor: cleanup time! Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 18
Test-Driven Development is a way of managing fear during programming. Kent Beck, Test-Driven Development by Example Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 19
The Cast 損 Me: Mathias Brandewinder mathias@clear-lines.com (clear-lines.com/blog) 損 Frameworks/Tools NUnit: www.nunit.org xUnit: xunit.codeplex.com/ Resharper: www.jetbrains.com/resharper/ 損 Books Kent Beck, Test Driven Development by Example Michael Feathers, Working Effectively with Legacy Code Roy Osherove, The Art of Unit Testing Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 20

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BizSpark SF Lightning Talk: "Refactoring and Test-Driven Development" by Mathias Brandewinder

  • 1. What is TDD? (answer: Test-Driven Development) and why you should care Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 1
  • 2. Once upon a Time Design Implement Test Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 2
  • 3. Stay buggy, my friends! Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 3
  • 4. Start with the tests! If I needed to Add 1 + 1 Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 4
  • 5. If I needed to Add 1 + 1 [Test] public void When_Adding_One_Plus_One_Answer_Should_Be_Two() { // Assert var expectedResult = 2; Assert.That(actualResult, Is.EqualTo(expectedResult)); } I would expect the answer to be 2 Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 5
  • 6. If I needed to Add 1 + 1 [Test] public void When_Adding_One_Plus_One_Answer_Should_Be_Two() { // Act var actualResult = calculator.Add(1, 1); // Assert var expectedResult = 2; Assert.That(actualResult, Is.EqualTo(expectedResult)); } I would need a Calculator Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 6
  • 7. If I needed to Add 1 + 1 [Test] public void When_Adding_One_Plus_One_Answer_Should_Be_Two() { // Arrange var calculator = new Calculator(); // Act var actualResult = calculator.Add(1, 1); // Assert var expectedResult = 2; Assert.That(actualResult, Is.EqualTo(expectedResult)); } I would need some code Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 7
  • 8. If I needed to Add 1 + 1 Does the code work? Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 8
  • 9. Testing frameworks MsTest Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 9
  • 10. Its not about Testing 損 Its about writing Code that works, now 損 Imagine you had implemented the feature 損 then implement it 損 Rinse & Repeat until you have no test to write Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 10
  • 11. Why should you care? Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 11
  • 12. The dreaded L word 息 www.dilbert.com Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 12
  • 13. To me, legacy code is simply code without tests. Michael Feathers, Working Effectively with Legacy Code Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 13
  • 14. Did I break everything? Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 14
  • 15. Tests: a Vise holding your code steady Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 15
  • 16. A good test is 損 Fast 損 Focused 損 Replicable 損 Automated Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 16
  • 17. Refactoring: improve the code structure, without changing its external behavior. Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 17
  • 18. Red, Green, Refactor 損 Red: write a little test that doesnt work 損 Green: make the test work quickly 損 Refactor: cleanup time! Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 18
  • 19. Test-Driven Development is a way of managing fear during programming. Kent Beck, Test-Driven Development by Example Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 19
  • 20. The Cast 損 Me: Mathias Brandewinder mathias@clear-lines.com (clear-lines.com/blog) 損 Frameworks/Tools NUnit: www.nunit.org xUnit: xunit.codeplex.com/ Resharper: www.jetbrains.com/resharper/ 損 Books Kent Beck, Test Driven Development by Example Michael Feathers, Working Effectively with Legacy Code Roy Osherove, The Art of Unit Testing Clear Lines Consulting 揃 clear-lines.com 11/8/2011 揃 20