Future Media BBC MMXI TDD at the BBC David Craddock, Jack Palfrey and Tom Canter.

Future Media BBC MMXI

TDD at the BBC

David Craddock, Jack Palfrey and Tom Canter


Who are we?

• David Craddock– Software Engineer

• Jack Palfrey – Developer In Test

• Tom Canter – Software Engineer


What do we do?

• Work in the BBC in Salford Quays.

– David works on the server-side code of Connected Red Button

– Jack teaches BDD and TDD principles to developers and writes the BDD framework tools we use

– Tom works on the front-end code of Connected Red Button


What is unit testing?


Benefits of Tests

• Finding problems early

• Code coverage upto 75%

• Reduce bug fixing time

• Monitoring your code base

• Gives confidence when low level changes are required

• Real low level regression tests

• Real documentation that never lies


Tests are useful for real world applications


Test last approach

Design

Code

Test


The TDD way

Test

Code

Refactor


What is TDD

• Think about what the test will do

• Write tests before code

• Tests ‘drive’

• An indication of ‘intent’

• Tests provide a specification and documentation


Test driven development by Kent Beck


TDD steps

• Implement a single failing test

• Watch it fail

• Write the simplest code to pass the test

• Rerun the test and watch it pass

• Refactor the code and tests to remove duplication

• Repeat


TDD best practices

• Keep your test and model code separate

• For every production class have a test class

• Write useful tests

• Agressively refactor production code

• Isolate your tests

• Maintain your tests

• Tests should test one thing

• Don't refactor with a failing test


Objections to writing test first


Today’s tools

• Cloud 9 + Python + PyUnit


Demo


Development at the BBC

• Work in teams with pair programming

• Agile planning / task boards / sprints / standups

• Source control - branching / commiting / merging

• BDD - Behaviour Driven Development

• Continuous Integration and automated builds

• XP techniques, pairing, TDD, no overtime


Development at the BBC (continued)

• Expected to pick up languages ad hoc, you are not solely a 'Java developer'

• Regular code reviews and discussions - very collaborative

• Regularly get sent on courses on many different technologies

• Masters course available

• Innovation time available, where you can work on what you want


Work at the BBC

• Graduate scheme - a 2 year scheme with 4 x 6 month developer placements

• Visit bbc.co.uk/careers/trainee-schemes/digitalmediascheme for more info and to apply, by 28th Feb for this year's intake

• Shorter work experience placements are available separately to the graduate scheme.


Practical session: Fizz Buzz

• Write a program that prints the integers from 1 to 100.

– But for multiples of three print "Fizz" instead of the number and for the multiples of five print "Buzz".

– For numbers which are multiples of both three and five print "FizzBuzz".

• But do this in a test-first (TDD) way


Practical

Future Media BBC MMXI TDD at the BBC David Craddock, Jack Palfrey and Tom Canter.

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Transcript of Future Media BBC MMXI TDD at the BBC David Craddock, Jack Palfrey and Tom Canter.