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Let's make this test suite run faster! - BeJUG
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dgageot
April 05, 2012
Programming
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Let's make this test suite run faster! - BeJUG
dgageot
April 05, 2012
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Transcript
Let's make this test suite run faster!
David Gageot Freelance developer @dgageot javabien.net
Why make a test suite run faster?
“ I firmly believe it can make your product better.
Faster to test leads to faster to write, deploy and use ” Anonymous bearded freelance developper
You test early and often. Right?
Continuous integration?
Continuous testing?
Continuous deployment?
Testing a lot can lead to waiting a lot
How wants his coding room to look like
Test suite duration can be contained
Jenkins slaves to the rescue
Jenkins slaves to the rescue. not.
Why complicated when it can be simple?
I’ll share a few easy tricks
“ I firmly believe it can make your product better.
Faster to test leads to faster to write, deploy and use ” Anonymous bearded freelance developper
How can we accelerate the tests? The Cheater The Lazy
The Cheater
Buy a faster machine. Tests are cpu/
Thank you Q/A
BUT single threaded tests get slower 0 25 50 75
100 2007 2008 2009 2010
Use all the cores with Maven3 mvn -T1 clean install
: 5:05s mvn -T4 clean install : 3:10s Beware of tests with side effects
It’s not just me
Use all the cores with JUnit/TestNG Beware of tests with
side effects
That’s it for cheaters No silver bullet
The Lazy
Delete useless tests It’s so simple, we don’t do it...
Even better, delete dead code
Even better, delete dead code Leads to deleting even more
useless tests
Work in a sandbox In-memory database H2 behaves much like
MySql As simple as changing an xml file The database is slow
It’s Not only SQL If going for NoSQL, choose a
server that can run in-process eg. Voldemort The network is slow
In-memory SMTP Server SubEtha SMTP
Abstract the filesystem Apache VFS (Virtual File System) Spring Resource...
In-memory everything As a bonus, tests will run smoother
Of course all of these are easier to setup at
the beginning of a project
The
5 minutes a day can make a difference
Don’t test business rules in integration Unit tests are often
a better place
Not the same scale of speed 10sec .01sec
Action #1 - Break the longer integration Into one faster
integration test and a lot of small
Action #2 - Mock the slowest layers Mocks are not
just for unit tests eg. with Spring and Mockito spies
Action #3 - Don’t test through the Selenium is often
overkill «But my application is complex!» «My users want complex features, My users want Ajax» «I need to test browser compatibility!»
Really?
Complexity has a cost That you pay each time tests
run
Test through the browser the strict Unit test Javascript
Action #4 - Sometimes be old school write (easier to
test) server-side code
Thank you Q/A
One more thing™ Action #0 - Simplify and optimize your
code Tests will run faster Keep that one secret...
Thank you Q/A