– t.d.d.  – Test Driven Development

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– t.d.d.  – Test Driven Development

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TDD_Slides

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t.d.d. 

Test Driven Development

What is it?

Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle: first the developer writes an (initially failing) automated test case that defines a desired improvement or new function, then produces the minimum amount of code to pass that test and finally refactors the new code to acceptable standards

Red - GREEN - Repeat..

That doesn't sound fun...

Well.. It's Not..

However

When we think of it Executable Specification , it 
changes our perspective and allows us to have 
more confidence that the code we are writing corresponds to the thing we actually want to produce.

Executable Specification?

But I already have a specification document
(probably in Word written by the sales team)

excuses not to test

  • I'll have to write 4x more code
  • It was just a tiny code change
  • I will test it once I complete this next thing
  • We don't have time
  • Big Bang Theory is on..

Reasons to test

  • It will make you a better developer
  • It will make your code better
  • Tests are always there once you write them
  • If the tests match the specifications, you can immediately know if the code does as well.
  • Ariane 5...

ariane 5 Rocket

Ariane 5 Rocket

  • 1996
  • 10 Years of Development
  • 40 seconds
  • $500 Million
  • 64 bit TO 16 bit conversion failure

TDD - Kata

Kata (型 or 形 literally: "form"?) is a Japanese word describing detailed choreographed patterns of movements practised either solo or in pairs

The basic goal of kata is to preserve and

transmit techniques. By practicing in a 

repetitive manner the learner develops the 

ability to execute those techniques and 

movements in a natural, reflex-like manner.

TDD - Kata

  • Try not to read ahead.
  • Do one task at a time. The trick is to learn to work incrementally.
  • Make sure you only test for correct inputs. there is no need to test for invalid inputs for this kata
  • String Calculator
  • Bowling Game
  • Roy Osherove

Resources

(PHP, but still good)