Chris GeorgeWebsite: www.mostly-testing.co.uk

@ChrisG0911

Easing the pain of legacy tests

Once upon a time…

Flagship product

Over 250,000 lines of code

Over 10,000 automated tests

Tests run in virtual machines

Multiple SQL Server versions

Continuous Integration

The real story…

Many attempts to fix over the years

== rising complexity== increasing instability

Myths, Preconceptions and Folklore

Don’t jump into the code…

Start with quick wins

Tests should clear up after themselves…

Exponential comparison…

# objects # Comparisons Approx time10 100 1 second100 10,000 1.7 mins1000 1,000,000 2.7 hours!

By the end of the week -

By the end of week 2 - only 1 failure!

95% passing

Discuss the problem/failure

Pattern #1

Pair & Review

Pattern #2

Pattern #3

Find and fix the quick wins

Pattern #4

De-mystify

Make best use of the skills on your team

Treat test code the same as product code

Don’t believe everything you hear

Most problems are not hard

Lessons learnt

</talk>Any Questions?

Chris GeorgeWebsite: www.mostly-testing.co.uk

@ChrisG0911