Picking The Right Set of Mobile Devices

1. Picking The Right Set of Mobile Devices By Brian Kitchener Software Quality Architect bkitchener@prototest.com

2. Overview About me Some Background The Problem Understanding Android How Apps Work Building a Device Matrix Example Matrices Conclusion

3. About Me • Software Quality Architect at ProtoTest • We're a mobile test lab that combines usability testing with quality assurance  to cultivate a great user experience • Project Architect, Technical Lead, Trainer. • Started in QA in 2001 • BA in Applied Computing from University of Denver • Testing background : Functional, Performance, UAT, Security, API, Database. • Automation : Selenium, WebDriver, WatiN, MonkeyTalk, SOASTA, Fitnesse, QTP, EggPlant, Squish • Languages : C#, Java, Ruby, Javascript

4. Background Information

5. Some Stats for 2012 • Mobile Apps achieved $17 billion in sales • 5.2 Mobile Subscribers • 1.2 Billion PC’s • 4.2 Billion people use a toothbrush • 1 Billion Smartphones • 722 Million Smartphones sold • 1.4 Million iOS + Android Apps • 25 developers = half of app revenue

6. iPhone - June 2007

7. About the iPhone • Steve Ballmer : Microsoft CEO • “There’s no chance the iPhone is going to gain significant market share. No chance.” • Patrick Stewart: • “Last Wednesday, I stupidly dropped my iPhone in the bath, and my life has sort of spiraled almost out of control.” • Jon Rubinstein – Palm CEO • Is there a toaster that also knows how to brew coffee? There is no such combined device, because it would not make anything better than an individual toaster or coffee machine. It works the same way with the iPod, the digital camera or mobile phone: it is important to have specialized devices. • Mike Lazaridis – Blackberry CEO • And so what [the iPhone] has actually done is increased our sales.

8. Android is the problem

9. And Then There Were Two… • Android unveiled November 2007 • First device was sold in October 2008. • Over 11,000 models have been released. • 48 Billion app installs • Over 1 Billion Android devices activated • 8 OS Revisions

10. OS Fragmentation

11. Device Fragmentation

12. Let’s do some math! • 16 device display categories • 20 different common resolutions • 8 OS versions • 6 Hardware Manufacturers • 4 Major cellular networks • 16 x 20 x 8 x 6 x 4 = 76,800 permutations • Pairwise approach = over 30 permutations • Who can afford to increase testing by 30X?

13. Our Approach Efficiency, not coverage Flexible: support small or large number of devices Understand how apps work to logically select criteria Use Market research to pick most common configurations Pick minimum and maximum boundary values for each criteria Choose a value that matches an edge case or abnormal configuration. Pick values that stress or tax the system

14. Understanding Android

15. Android • Built and Maintained by Google • Open Source • Built on Linux kernel • ARM • X86 Ports • Built to support almost any type of device • Phones, tablets, phablets, media players, tv’s, watches, etc. • Device Manufacturers customize code.

16. Example: Kindle Fire • Forked Android 2.3 • Not updateable • Customized UI • Separate App store • Not all android apps work • Custom web browser

17. The Operating System • Google Releases “stock” versions • 10 Major Releases since 2008 • API Level, not Version • Device manufacturers like to customize the OS • Drivers, libraries, UI • “Stock” OS available in Nexus devices or an Emulator

18. Simulators / Emulators • Simulator imitates the software layer • OS and Libraries • Apple provides a simulator in xCode IDE • Emulator duplicates the hardware and software • Processor and Memory • Cannot mimic GPU, GPS, accelerometer • Always run stock OS • Can be used to test some functionality • Should always test on a physical device too

19. The Processor • ARM RISC-based instruction set • Specification defined by ARM holdings • 32 bit • Same as iOS • X86 patches and ports • It’s only a spec, can be modified.

20. SoC – System On A Chip • Main Board • Processor • RAM Bus • GPU • May include : • Cellular • WiFi • NFC • GPS • Bluetooth

21. 2 Samsung Galaxy S4s Quallcomm Snapdragon • Quallcomm Krait 300 • Quad core ARMv7 Cortex A15 Architecture • Adreno 320 GPU • Dual Channel 533Mhz Bus • Integrated LTE Samsung Exynos 5 Octa • Samsung Big.little processor • Quad core Cortex A 15 • Quad core Cortex A7 • PowerVR SGX 544 GPU • Dual Channel 800Mhz Bus • No Integrated LTE

22. Common SoC

23. Resolution is not enough • Unlimited number of screen sizes available • Screens range from 3” to 11” • Each screen has a resolution, same as a monitor • If you increase the resolution everything shrinks! • Pixels per Inch = Density • Screen Size + Density = Display Bucket • Resolution is not enough!

24. The Display Buckets Size : • Xlarge : 8” - 10” tablet. • Large : 5” - 7” tablet. • Normal : 3.5” - 5” phones. • Small : 3” - 3.5” phones. Density : • ldpi = Low DPI (~120) • mdpi = Medium DPI (~160) • hdpi = High DPI (~240) • xhdpi = Extra High DPI (~320)

25. Display Buckets • Galaxy S3 • 1280 x 720 • Xhdpi density (331ppi) • Normal screen (4.7”) • Galaxy Tab 10.1 • 1280 x 800 • ldpi density (149ppi) • Xlargesceren (10.1”) • Galaxy Note LTE • 1280 x 800 • hdpi density (285ppi) • Large Screen (5.5”)

26. Market Analysis

27. Aspect Ratio • UI is manipulated from code • Density Pixels adjust for screen size • But can use regular pixels! • Need to take both X and Y into account! • Easy to overlap or hide things • Includes orientation • Some devices include an aspect ratio changer! (LG Optimus Vu)

28. Cellular Carrier • Four Major US Networks • Verizon, Sprint, AT&T, T-Mobile • Some phone interoperability • 2 protocols • GSM – T-Mobile AT&T • CDMA – Verizon and Sprint • Carriers assigned specific frequency bands • LTE will be new standard - But spectrum issues will prevent cross-network phones • So if the phone supports the carrier’s protocol and band it can theoretically connect.

29. How apps work

30. How Apps work • Apps need to work on all screen sizes • May not be functional • May be wasted space • May not make sense • Apps define XML layouts similar to HTML • Node structure • Static Content – Images, etc • Dynamic Content – Color, Text, etc.

31. Layouts and Fragments • XML Fragments are reusable components • Layouts stitch together fragments for a specific sized device • App may need different flow for tablet vs phone

32. Building The Device Matrix

33. Our Criteria • Operating System • OS customizations, missing libraries, driver issues, • Screen Size • Rendering issues, usability, missing layouts • Pixel Density • Density Independence, missing layouts. • Aspect Ratio • X,Y calculations, overlapping panels, display issues • SoC • Hardware performance, Instruction set, battery, signal • Carrier • Network protocol, speed, responsiveness, packet loss

34. The Goal Efficiency, not coverage! Build a set of devices to be used for app and website testing. Know when to update them Define a list of simple categories of devices Pick devices that offer broad coverage Adjust the number of devices based upon needed coverage

35. Categorical Approach • Define scope • Android, iOS, phone, tablet, etc. • Understand Testing requirements • Self-descriptive Names • Help to broaden coverage • Will adjust devices chosen to cover our criteria • Should be apparent when to update a device • Spread coverage : • Usage -> Edge Cases -> Strange -> Stress

36. Example Categories • Common • Matches most common display configuration • Newest • Latest OS version, largest screen, highest resolution • Oldest • Oldest, slowest, smallest device. • Abnormal • Non-standard OS, aspect ratio, orientation, size • Popular • Most popular device in terms of sales • Budget • Low-priced new model. Tend to have strange specs • Flagship • Nexus device running stock Android OS • Catch-All • Cover any missing criteria

37. Android Phone Matrix

38. iOS Matrix

39. Conclusion • Understanding how everything works allows us to logically select devices. • A large number of permutations can be covered in few devices • If additional coverage is needed additional devices can be added • White Paper : • http://www.prototest.com : • Building the Ultimate Device Matrix