Testing The Legacy: Making Existing Applications Testable Without Epic Efforts

testing theLegacy

making existing applications testablewithout epic efforts

Alex Leonovalex@knowledgelab.nz

@alexanderleonov

Why is it not done yet?• no people• no time• no money

Why is it not done yet?• no people• no time• no money

doesn’t hurt enough

How to eat an elephant?• piece• by• piece

How to make it testable?• bug• by• bug

if they say it’s Impossible

remember that it’simpossible for them

you need to get

The Commitment

Automated Tests

Old Application New Application

Old Application

Old Code

Automated Tests

Bubble WrapOld Application

Old CodeLogic

Automated Tests

Bubble WrapOld Application

Old CodeProxy

New Application

Services

Automated Tests

Old Application

Old Interfaces

New ApplicationInterfaces

Services

Automated Tests

Old Application New Application

Automated Tests

New Application

The Easy Wayor

The Good Way

The Easy Way• make code with bugfix testable• write down gherkins• hope someone updates them

The Good Way• make bugfix testable• make “feature” testable• make executable gherkins• add this to the Definition of Done

Things to Remember• view features as services• stateless is better than stateful• don’t test the whole all the time• don’t let it slip

Recap• get commitment• don’t compromise on quality• automate everything you touch• bubble-wrap old stuff• start small and grow over time

Alex Leonovalex@knowledgelab.nz@alexanderleonov

testing theLegacy