The document discusses the importance of testability in software development. It argues that focusing on testability, rather than just features, can lead to important benefits like reduced time to start testing, lower unplanned downtimes, and increased ability to observe and understand the entire system. The document advocates for approaches like enabling faster branching to devices for testing, more automation, and greater collaboration between development and operations teams to improve testability.

1. “The most dangerous strategy is
to jump a chasm in two leaps.” ~
Benjamin Disraeli

2. Ash Winter
Short stuff here:
@northern_tester
Long stuff here:

3. Shift Testability!

4. Shifting Debate
• Left towards
development
• Right
towards
operations
• Or both!

5. Courtesy of Cindy Sridharan @copyconstruct
TESTABILITY FTW

6. Hard to Test?
• Do more of
the testing
that
testers do
• Hiring more
testers

7. Hard to Test?
• Moar
automation
• Making a
mockery
• Fire and
forget into
Production

8. Think Testability!
• Observe
• Control
• Understand
• Testable ==
Supportable
• Useful to all
not just Dev
and Ops!

9. Heuristics of Software
Testability

10. • Distracted
by
features…
• Where is
the biggest
gain to be
made in the
system?
Faffing with features?

11. • Not saying
no value…
• Testers
testing
features
finds
important
problems...
Disclaimer

12. • Time taken to start testing
• Unwittingly extended and/or
unplanned downtime
Two Metrics

13. • Mobile app
• Local dev
environment
• DNS
• Hours between
pull branch
to test on
device
Time to testing

14. Time to Testing
• Testing was
always lagging
• Exhausted by
the time
testing began
• Important
problems
missed

15. Testability FTW!
• Branch to device in minutes
• Devs testing on real devices!

16. • Infra “tribe”
• Planned &
unplanned
downtime
• Hiring testers
• Build vast
environments
• Big bangs
Costly Downtime

17. Costly Downtime
• Infra
problems
> feature
problems
• £250k per
hour
worth

18. Testability FTW!
• Much more empathy
• Lower unplanned/extended
downtime

19. Conclusion!

20. The Three Ways of
DevOps
• Amplify
Feedback
• Experiment
& learn
• Systems
Thinking

21. Hang on, isn’t that
testability?
• Observe system
feedback
• Control system
state to
hypothesize
• Understand whole
system, optimise
globally

22. Questions