Software Quality

What happened to those nice words, “Software Quality”?

A grumpy developer’s perspective

And 4 simple steps

Adrian Kosmaczewski

Software developer

since 1996

Houston,

“Our society depends on software”

Bjarne Stroustrup

Yes, but:

Software Sucks

(some of it)

(mine does)

(sometimes)

Integer overﬂow

Nobody died

Therac-25

6 people died

Overexposed to radiation

1982 Soviet Gas Pipeline Explosion

Largest non-atomic explosion of history

Bug injected by CIA

1988 Morris worm

First network worm

Buffer overﬂow

1988 Russian “Phobos” Probe in Mars

Bad thruster deactivation

1992 London Ambulance System

No ofﬁcial statistics about casualties

1993 Pentium bug

*giggle*

1998 USS Yorktown

Ship lost in the ocean

Divide by zero error

1999 Mars Climate Orbiter

Miles or kilometers?

1999 Mars Polar Lander

Vibrations? Cut the engines!

Geez, it was the atmosphere... not the ground!

2000 National Cancer Institute, Panama

8 patients die

20 other overdosed

Doctors indicted for murder

2003 USA Blackout

Race condition

2006 Mars Global Surveyor

Motor dead? Yes? No!

Ever heard about the CHAOS report? http://www.standishgroup.com/

Status 1994 2006 Success 16% 35% Challenged 53% 46% Failed 31% 19% Source: http://tinyurl.com/yodqnw

What about us?

No space missions

Smaller projects

Similar problems

Software is expensive

ISO Certiﬁcations are worthless

CMMI certiﬁcations are (less) worthless

Software Quality theory is boring

Well, almost

Avoid being on The Daily WTF

4 steps

1. Pass the Joel Test 2. Avoid Open Spaces 3. At least write unit tests 4. Communicate

1 The Joel Test http://tinyurl.com/1s8w

The Joel Test 1. Do you use source control? 2. Can you make a build in one step? 3. Do you make daily builds? 4. Do you have a bug database? 5. Do you ﬁx bugs before writing new code? 6. Do you have an up-to-date schedule? 7. Do you have a spec? 8. Do programmers have quiet working conditions? 9. Do you use the best tools money can buy? 10. Do you have testers? 11. Do new candidates write code during their interview? 12. Do you do hallway usability testing?

How much is your score?

Be honest! :)

2 Avoid open spaces

Cheaper?

Why not? •Noise •Interruptions •Phones •iPods •Lack of privacy

Ever heard about “Peopleware”?

Buy it and read it

“Flow”

http://www.ndesign-studio.com/images/portfolio/graphic/ﬂow-1.jpg

Consequences •Low quality •Late delivery •Burnout •Turnover

Turnover is your enemy # 1

Cheaper in the short term means expensive in the long run

3 At least, write unit tests

You’ll thank me

• JUnit • JSUnit (JavaScript) • NUnit • WOTest (ObjC) • PyUnit • PHPUnit • Unit::Test (Ruby) • FoxUnit (FoxPro) • RSpec (Ruby) • Selenium • CppUnit (C++) • lisp-unit • Boost Test (C++) • DUnit • Autounit (C) • SchemeUnit

Refactoring

Documentation

Usage examples

Maintenance

Architecture

API Design

Performance

Good karma

How much testing?

Enough

Don’t become fanatic

(at least) One for every bug

Avoid regressions

Run them at every build

Script that build!

4 Communicate

Visual Studio Team System

(yuck!)

Bugzilla

Meetings

Don’t make them regular

Make them ad-hoc

Prefer code reviews

Client on board

Not always possible!

But extremely useful

Conclusion

1. Pass the Joel Test 2. Avoid Open Spaces 3. At least write unit tests 4. Communicate

Thanks!

Questions?

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Software Quality

by Adrian Kosmaczewski on Sep 10, 2009

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Software Quality — Presentation Transcript