We all know that Appium can do (almost) everything you tell it to do, but in the end we always ask it to do the same thing: to automate our happy and/or our error flow. The result can give us the confirmation that the user can still buy a product, or verify if his bank account still has a positive balance. But what if we need to know more than that: what if we also need to verify the layout of our app? The answer would be easy, as there are plenty of open-source or paid solutions that can help you with that. However, almost all of these solutions focus on web/hybrid apps, not on native iOS and or Android apps. Wim faced this challenge when he was automating a React Native app for a customer. There was no image comparison tool that could do what he wanted it to do, so he rolled up his sleeves and started building one. In this talk, Wim will walk down the path he took and he will explain: - Why he used ResembleJS as a core visual comparison solution - The things he learned about Appium in the process (pro tips!) - The differences between iOS and Android and how he managed to solve this in one cross-platform solution - The pros and cons of the solution

1. BUILDING YOUR OWN NATIVE APP
VISUAL TESTING MODULE WITH APPIUM
Wim Selles,
Sr. Solutions Architect @Sauce Labs

2. IT’S NOT ABOUT ME
! :@wswebcreation
" : https://github.com/wswebcreation

3. IDEA

4. IDEA

5. REQUIREMENTS
• Native App support
• Cross platform
• Integrate WebdriverIO
• Paid tools === trial first
• Support blockouts
• Support element screenshots/bounding box
FOR A VISUAL REGRESSION / TESTING SOLUTION

6. BLOCKOUTS
Status-/navigation-/
home indicator bar
WHY …?
Animations Dynamic text

7. RESEARCH
VISUAL REGRESSION / TESTING FOR NATIVE APPS
iOSSnapshotTestCase
Nakal
sightr.io
screenshot-tests-for-android

8. RESULT
VISUAL REGRESSION / TESTING FOR NATIVE APPS
Requirements
screenshot-tests-
for-android
iOSSnapshot
TestCase
Nakal sightr.io VisWiz Applitools
Native apps support Yes Yes Yes Yes Yes Yes
WebdriverIO support
- JS
- No extra env
dependencies
No No No No Yes
Not for
native apps
Trial? Open source Open source
Open
source
Beta Yes Yes
Image diff Yes, basic Yes, basic Yes Yes Yes, basic Yes, extensive
Blockouts No No Yes and no No no Yes
Element screenshots No No No No No No
Bounding box No No No No No Yes

9. RESULT
VISUAL REGRESSION / TESTING FOR NATIVE APPS
Requirements
screenshot-tests-
for-android
iOSSnapshot
TestCase
Nakal sightr.io VisWiz Applitools
Native apps support Yes Yes Yes Yes Yes Yes
WebdriverIO support
- JS
- No extra env
dependencies
No No No No Yes
Not for
native apps
Trial? Open source Open source
Open
source
Beta Yes Yes
Image diff Yes, basic Yes, basic Yes Yes Yes, basic Yes, extensive
Blockouts No No Yes and no No no Yes
Element screenshots No No No No No No
Bounding box No No No No No Yes

10. RESULT
VISUAL REGRESSION / TESTING FOR NATIVE APPS
Requirements
screenshot-tests-
for-android
iOSSnapshot
TestCase
Nakal sightr.io VisWiz Applitools
Native apps support Yes Yes Yes Yes Yes Yes
WebdriverIO support
- JS
- No extra env
dependencies
No No No No Yes
Not for
native apps
Trial? Open source Open source
Open
source
Beta Yes Yes
Image diff Yes, basic Yes, basic Yes Yes Yes, basic Yes, extensive
Blockouts No No Yes and no No no Yes
Element screenshots No No No No No No
Bounding box No No No No No Yes

11. RESULT
VISUAL REGRESSION / TESTING FOR NATIVE APPS
Requirements
screenshot-tests-
for-android
iOSSnapshot
TestCase
Nakal sightr.io VisWiz Applitools
Native apps support Yes Yes Yes Yes Yes Yes
WebdriverIO support
- JS
- No extra env
dependencies
No No No No Yes
Not for
native apps
Trial? Open source Open source
Open
source
Beta Yes Yes
Image diff Yes, basic Yes, basic Yes Yes Yes, basic Yes, extensive
Blockouts No No Yes and no No no Yes
Element screenshots No No No No No No
Bounding box No No No No No Yes

12. RESULT
VISUAL REGRESSION / TESTING FOR NATIVE APPS
Requirements
screenshot-tests-
for-android
iOSSnapshot
TestCase
Nakal sightr.io VisWiz Applitools
Native apps support Yes Yes Yes Yes Yes Yes
WebdriverIO support
- JS
- No extra env
dependencies
No No No No Yes
Not for
native apps
Trial? Open source Open source
Open
source
Beta Yes Yes
Image diff Yes, basic Yes, basic Yes Yes Yes, basic Yes, extensive
Blockouts No No Yes and no No no Yes
Element screenshots No No No No No No
Bounding box No No No No No Yes
?

13. CONCLUSION
WHAT TO DO?

14. LOGIC
WHO SHOULD DO WHAT?
Requirements Module Comparison engine
Actively maintained - Yes
Environment dependencies No No
Blockout(s) Yes, determine and provide Yes
Element screenshot Yes -
Create baseline Yes -
Screenshots per device Yes -
Support compare options
(for example antialiasing)
Yes Yes

15. LOGIC
WHO SHOULD DO WHAT?
Requirements Module Comparison engine
Actively maintained - Yes
Environment dependencies No No
Blockout(s) Yes, determine and provide Yes
Element screenshot Yes -
Create baseline Yes -
Screenshots per device Yes -
Support compare options
(for example antialiasing)
Yes Yes

16. JAVASCRIPT PIXEL-BY-PIXEL LIBRARIES
js-imagediff
image-diff
Rembrandt.JS
LooksSamepixelmatch
node-opencv
img-diff-js
Pixel-Diff
Resemble.JS

17. JAVASCRIPT PIXEL-BY-PIXEL LIBRARIES
js-imagediff
image-diff
Rembrandt.JS
LooksSamepixelmatch
node-opencv
img-diff-js
Pixel-Diff
Resemble.JS

18. JAVASCRIPT PIXEL-BY-PIXEL LIBRARIES
js-imagediff
image-diff
Rembrandt.JS
LooksSamepixelmatch
node-opencv
img-diff-js
Pixel-Diff
Resemble.JS

19. JAVASCRIPT PIXEL-BY-PIXEL LIBRARIES
js-imagediff
image-diff
Rembrandt.JS
LooksSamepixelmatch
node-opencv
img-diff-js
Pixel-Diff
Resemble.JS

20. JAVASCRIPT PIXEL-BY-PIXEL LIBRARIES
js-imagediff
image-diff
Rembrandt.JS
LooksSamepixelmatch
node-opencv
img-diff-js
Pixel-Diff
Resemble.JS

21. CONCLUSION

22. CONCLUSION

23. • saveScreen
WHAT SHOULD IT DO?

24. • saveScreen
• compareScreen
WHAT SHOULD IT DO?

25. • saveScreen
• compareScreen
• saveElement
WHAT SHOULD IT DO?

26. • saveScreen
• compareScreen
• saveElement
• compareElement
WHAT SHOULD IT DO?

27. SAVESCREEN
WHAT SHOULD IT DO?

28. COMPARESCREEN
WHERE COULD IT GO WRONG, WHERE COULD IT CAUSE FLAKINESS?
Navigation bar Home bar indicatorStatus bar

29. STATUS BAR
• Android and iOS differ in height
• iOS OS versions / devices differ
• Android OS versions / devices differ
• Cross platform / device solution

35. DEMO

41. NAVIGATION BAR
• Android OS versions / devices differ
• Not each device has a tool/navigation bar
• Cross device solution
FOR ANDROID

43. HOME BAR INDICATOR
● Currently 2 sizes
● The behaviour can be adjusted
IPHONE X SERIES

45. SAVEELEMENT
WHAT SHOULD IT DO?

46. SAVEELEMENT
WHAT SHOULD IT DO?

47. SAVEELEMENT
WHAT SHOULD IT DO?

48. SAVEELEMENT
EXTRA POWER

49. COMPAREELEMENT
● Comparing (options) the
same as for compareScreen
● Element block-outs
more complex
WHAT SHOULD IT DO?

50. USE CASE
React Native
0.54
React Native
0.57

51. USE CASE
React Native
0.54
React Native
0.57

52. USE CASE

53. DISCLAIMER
Cons
● Basic comparison
● Impact on project size
● Limited blockout options
● No dashboard
Pro’s
● Open Source
● The (module) logic is easy
● Easy cross platform/device blockout
logic
driver.compareScreen(
'compareScreen-elementBlockOuts', {
elementBlockOuts: [
// block out element 1
{ element: LoginScreen.loginButton },
// block out element 2 with margin
{ element: LoginScreen.email, margin: 50},
],
}
);

54. WANT TO USE IT?
https://github.com/wswebcreation/wdio-native-app-compare

55. WANT TO USE IT?

56. THANK YOU.