Usable Software Design sclc.pdf

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Usable Software Design There’s no solution without a problem Johan Martinsson, developer. @JOHAN_ALPS

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@JOHAN_ALPS Design … ... It’s not just what it looks like and feels like. Design is how it works. https://www.flickr.com/photos/8010717@N02/6216457030 CC BY 2.0

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Alexandru Bolboaca @JOHAN_ALPS leanpub.com/usablesoftwaredesign

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We’re all designers @JOHAN_ALPS @MARGAUXLERGO 4 The user of software design is the developer Alexandru Bolboaca

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It’s not the users fault, it’s the designs fault @JOHAN_ALPS Source : http://www.lsd-mag.com/blog/design-inconfortable/

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A definition @JOHAN_ALPS Nielson (1994)

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Identify design problems @JOHAN_ALPS

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Interviews What was difficult to do in the past weeks? What areas of the code were most difficult to understand When were you afraid that your changes might be wrong? Alexandru Bolboaca @JOHAN_ALPS

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Usability tests « Needs to be cheap enough that you’ll do it! » Watch someone start a story using your code - Don’t help - Ask them to vocalize @JOHAN_ALPS

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Code review @JOHAN_ALPS I don’t like the code! Is there a usability problem?

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Team Agreement 1. Code written to be read 2. Easy to find where to modify 3. Minimal ripple effect 4. Simple AND easy to validate 5. Limited duplication A federating concept

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Parallels with code @JOHAN_ALPS

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Incitation @JOHAN_ALPS Push or pull? Push, but where? Push!

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Incitation @JOHAN_ALPS

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Consistency @JOHAN_ALPS Source : http://lesmoyensgrands.over-blog.com

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Consistency @JOHAN_ALPS

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Local Consistency @JOHAN_ALPS - 1972

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Local Consistency @JOHAN_ALPS

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Compatibility @JOHAN_ALPS msPaint Adobe Photoshop

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Compatibility @JOHAN_ALPS

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Compatibility @JOHAN_ALPS Listen to your users, don’t obey them

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TDD and usability TDD ◦ Affirmative @JOHAN_ALPS Trial & error ◦ Exploratory

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TDD and usability @JOHAN_ALPS Resources.delete() Broadcast() resetCurrent() toggleSelectionMode() Delete() Manager.fire() Navigator.delete() Shot gun surgery. Learn/memorability problem

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TDD and usability TDD requires cognitive mastery. If we don’t have that, then we have a usability problem @JOHAN_ALPS

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Readability @JOHAN_ALPS Wikipédia Wikiwand

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Readability @JOHAN_ALPS

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Information density @JOHAN_ALPS Cdiscount Google

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Information density @JOHAN_ALPS One level of abstraction Reveal intent

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Documentation @JOHAN_ALPS When the design is obvious, documentation is waste

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@JOHAN_ALPS

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@JOHAN_ALPS

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Errors @JOHAN_ALPS

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Make errors impossible @JOHAN_ALPS Google Agenda

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Make errors impossible @JOHAN_ALPS // Mandatory parameters in constructor // Type parameters

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It’s not the users fault, it’s the designs fault @JOHAN_ALPS Source : http://www.lsd-mag.com/blog/design-inconfortable/

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Make errors impossible Two time instantiation Temporal coupling Coupling without cohesion … @JOHAN_ALPS

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Fix errors @JOHAN_ALPS

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Encapsulate primitives Fix errors @JOHAN_ALPS

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@JOHAN_ALPS github.com/martinsson/BugsZero-Kata

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Rapid feedback @JOHAN_ALPS Amazon Cdiscount

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Rapid feedback @JOHAN_ALPS $ npm test Executed 364 of 364 SUCCESS (2.663 secs) TOTAL: 364 SUCCESS

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Funnel of feedback @JOHAN_ALPS IDE Unit tests CI - tests Code review Dev ..etc

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Dig deeper @JOHAN_ALPS

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Conclusion It’s not the users fault à Design You’re not your user à Test Starts with Whyà Federating concept @JOHAN_ALPS BUSINESS NEEDS USABLE CODE