escaping test hell - our journey - xpdays ukraine 2013
DESCRIPTION
My updated slides about the journey to hell and back to normality wrt automated tests at scale. Based on real 10+ years experience of JIRA development teams. I delivered this talk at XPDays in Kiev in October 2013.TRANSCRIPT
About me
• Coding for 30 years, now only in "free time"
• Agile Practices (inc. TDD) since 2003
• Dev Nerd, Tech Leader, Agile Coach, Speaker, PHB
• 6 years with Atlassian (JIRA Dev Manager)
• Spartez Co-founder & CEO
XP PromiseC
ost
of C
hang
e
Time
WaterfallXP
1.5 year ago
Almost 10 years of accumulating
garbage automatic tests
About 20 000 tests on all levels of abstraction
Very slow (even hours)and fragile feedback loop
Serious performance and reliability issues
Dispirited devs accepting RED as a norm
FeedbackSpeed
`Test
Quality
Test Code is Not Trash
Design
MaintainRefactor
Share
Review
Prune
Respect
Discuss
Restructure
Test Pyramid
Unit Tests (including QUnit)
REST / HTML Tests
Selenium
Optimum Balance
Isolation Speed Coverage Level Access Effort
Dangerous to temper with
MaintainabilityQuality / Determinism
Now
People - MotivationMaking GREEN the norm
Shades of RedShades of Green
Pragmatic CI Health
Build Tiers and Policy
Tier A1 - green soon after all commits
Tier A2 - green at the end of the day
Tier A3 - green at the end of the iteration
unit tests and functional* tests
WebDriver and bundled plugins tests
supported platforms tests, compatibility tests
Wallboards: Constant
Awareness
Extensive Training
• assertThat over assertTrue/False and assertEquals
• avoiding races - Atlassian Selenium with its TimedElement
• Favouring unit tests over functional tests
• Promoting Page Objects
• Brownbags, blogs, code reviews
Quality
Automatic Flakiness Detection Quarantine
Re-run failed tests and see if they pass
Quarantine - Healing
SlowMo - expose races
Selenium 1
Selenium ditching Sky did not fall in
Ditching - benefits
• Freed build agents - better system throughput
• Boosted morale
• Gazillion of developer hours saved
• Money saved on infrastructure
Ditching - due diligence
• conducting the audit - analysis of the coverage we lost
• determining which tests needs to rewritten (e.g. security related)
• rewriting some of the tests (good job for new hires + a senior mentor)
Flaky Browser-based TestsRaces between test code and asynchronous page logic
Playing with "loading" CSS class does not really help
Races Removal with Tracing// in the browser:function mySearchClickHandler() { doSomeXhr().always(function() { // This executes when the XHR has completed (either success or failure) JIRA.trace("search.completed"); });}// In production code JIRA.trace is a no-op
// in my page object:@InjectTraceContext traceContext; public SearchResults doASearch() { Tracer snapshot = traceContext.checkpoint(); getSearchButton().click(); // causes mySearchClickHandler to be invoked // This waits until the "search.completed" // event has been emitted, *after* previous snapshot traceContext.waitFor(snapshot, "search.completed"); return pageBinder.bind(SearchResults.class);}
Can we halve our build times?
Speed
Parallel Execution - Theory
End of Build
Batches
Start of Build Time
Parallel Execution
End of Build
Batches
Start of Build Time
Parallel Execution - Reality Bites
End of Build
A1
Batches
Start of Build
Agent availability
Time
Dynamic Test Execution Dispatch - Hallelujah
"You can't manage what you can't measure."
not by W. Edwards Deming
If you believe just in it
you are doomed.
You can't improve something if you can't measure it
Profiler, Build statistics, Logs, statsd → Graphite
Anatomy of Build*
CompilationPackaging
Executing Tests
Fetching Dependencies
*Any resemblance to maven build is entirely accidental
SCM Update
Agent Availability/Setup
Publishing Results
JIRA Unit Tests Build
Compilation (7min)
Packaging (0min)
Executing Tests (7min)Fetching Dependencies (1.5min)
SCM Update (2min)
Agent Availability/Setup (mean 10min)
Publishing Results (1min)
Decreasing Test Execution Time
to ZERRO alone would not let us
achieve our goal!
Agent Availability/Setup
• starved builds due to busy agents building very long builds
• time synchronization issue - NTPD problem
Fixes applied
• Proximity of SCM repo
• shallow git clones are not so fast and lightweight + generating extra git server CPU load
• git clone per agent/plan + git pull + git clone per build (hard links!)
• Atlassian Stash was thankful (queue)
SCM Update - Checkout time
2 min → 5 seconds
Trade disk space for speed
• Fix Predator
• Sandboxing/isolation agent trade-off:rm -rf $HOME/.m2/repository/com/atlassian/*
intofind $HOME/.m2/repository/com/atlassian/ -name “*SNAPSHOT*” | xargs rm
• Network hardware failure found (dropping packets)
Fetching Dependencies
1.5 min → 10 seconds
Compilation
• Restructuring multi-pom maven project and dependencies
• Maven 3 parallel compilation FTW -T 1.5C*optimal factor thanks to scientific trial and error research
7 min → 1 min
Unit Test Execution
• Splitting unit tests into 2 buckets: good and legacy (much longer)
• Maven 3 parallel test execution (-T 1.5C)
7 min → 5 min
3000 poor tests(5min)
11000 good tests(1.5min)
Functional Tests
• Selenium 1 removal did help
• Faster reset/restore (avoid unnecessary stuff, intercepting SQL operations for debug purposes - building stacktraces is costly)
• Restoring via Backdoor REST API
• Using REST API for common setup/teardown operations
Functional Tests
We like this trend
Publishing Results
• Server log allocation per test → using now Backdoor REST API (was Selenium)
• Bamboo DB performance degradation for rich build history - to be addressed
1 min → 40 s
Unexpected Problem
• Stability issues with our CI server
• The bottleneck changed from I/O to CPU
• Too many agents per physical machine
JIRA Unit Tests Build Improved
Compilation (1min)
Packaging (0min)
Executing Tests (5min)
Fetching Dependencies (10sec)
SCM Update (5sec)
Agent Availability/Setup (3min)*
Publishing Results (40sec)
Improvements Summary
Tests Before After Improvement %
Unit tests 29 min 17 min 41%
Functional tests 56 min 34 min 39%
WebDriver tests 39 min 21 min 46%
Overall 124 min 72 min 42%
* Additional ca. 5% improvement expected once new git clone strategy is consistently rolled-out everywhere
The Quality Follows
But that's still bad
We want CI feedback loop in a few minutes maximum
Splitting The Codebase
Codebase Split - Problems
• Organizational concerns - understanding, managing, integrating, releasing
• Mindset change - if something worked for 10 years why to change it?
• We damned ourselves with big buckets for all tests - where do they belong to?
Splitting code base• Step 0 - JIRA Importers Plugin (3.5 years ago)
• Step 1- New Issue View and NavigatorJIRA 6.0
We are still escaping hell. Hell sucks in your soul.
Conclusions
• Visibility and problem awareness help
• Maintaing huge testbed is difficult and costly
• Measure the problem, measure improvements
• No prejudice - no sacred cows
• Automated tests are not one-off investment, it's a continuous journey
• Performance is a damn important feature
Revised XP PromiseC
ost
of C
hang
e
Time
WaterfallXPSad Reality
Interested in such stuff?
Talk to me at the conference or visit http://www.spartez.com/careers
We are hiring in Gdańsk
• Turtle - by Jonathan Zander, CC-BY-SA-3.0
• Loading - by MatthewJ13, CC-SA-3.0
• Magic Potion - by Koolmann1, CC-BY-SA-2.0
• Merlin Tool - by By L. Mahin, CC-BY-SA-3.0
• Choose Pills - by *rockysprings, CC-BY-SA-3.0
• Flashing Red Light - bt Chris Phan, CC BY 2.0
Images - Credits
Thank You!
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