My journey

as a developerOr how I learnt to release high quality software frequently

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Fast coding

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Feeling proud!

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No automated tests

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Lots of manual testing

“Software and cathedrals are much the same – we first build them, then we pray.”

- Samuel T. Redwine, Jr.

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No confidence in the releases

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A fair few bugs

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No regression suite

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Maintenance was a nightmare

“Don’t use hands to do things that can be efficiently done by the computer.”

– Tom Duff

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Enter unit testing!

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Code first

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If manual testing is hard and time consuming, automate it!

Code first is hard

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Adding tests after the code is implemented without unit testing in mind is hard!

Test first works better

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What’s this TDD everyone talks about?

No TDD

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So much better

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• Easier to write unit tests

• A lot less manual testing

• Faster releases

• Easier maintenance

There were still a few bugs!

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Tdd: not a silver bullet

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Unit tests cover a lot of things; but a lot of bugs happen in interaction between

units.

Integration Testing

to the rescue

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Test a few things together

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If the bug is in interactions, test the units together

Caught a lot of bugs

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And the automation was a lot tighter

There were still UI related bugs!

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Automated UI Testing

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Test it end to end

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Automated UI tests run through everything end to end!

Demo – UI Automation

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But now business can’t read my test cases

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No manual testing means

No test cases which means

Hard to verify behavior by the business which means

Programmers could write the wrong thing

Self testing code: no silver bullet

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• You misunderstand the requirements

• You write the wrong test

• You write the wrong code to pass the wrong test

• You have a green test suite

• But you’ve implemented the wrong thing

“The most important single aspect of software development is to be clear about what you are trying to build.”

– Bjarne Stroustrup

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BDD to the rescue

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Behavior Driven Development

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bridges the communication gap

Behavior Driven Development Benefits

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• Getting verification from BAs

• Automated regression suite defined by BAs

• Always up-to-date software requirements

• YAGNI

Demo – BDD

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Acceptance Test Driven Development

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BDD + UI Automation => AWESOME

But this is so slow to run. I’m bored!!

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Enter

Continuous Integration

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Continuous Integration

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• Integrate the code frequently

• Build the code on each commit

• Run the fast tests on each commit

• Run the slow tests on schedules

CI Rules

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• Fixing red CI is the highest priority

• If you break the build, you do push ups

• No one pulls from a red build

• No one pushes to a red build

“If it hurts, do it more frequently, and bring the pain forward.”

– Jez Humble

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Enter

Continuous Delivery

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Push to production continuously

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If everything is tested and verified properly, then you can push it to

production at any time!

Demo – CI & CD

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It feels good

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And the guys who wanted my tests to fail

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THANK YOUMehdi KhaliliSenior Consultant @ ThoughtWorks

www.mehdi-khalili.com@MehdiKhalili