[Android] Updated the official Fundamentals of Testing doc

Fundamentals of Testing has been updated based on AndroidX series.

As I have proposed similar pyramid for a long time to friends of mine and colleagues. e.g. [English]Test automation design for Cookpad’s global Android app, 2018, [Japanese]Android/iOSアプリのテストの区分戦略, 2016

In the article, below is mapped.

• Local unit tests => small tests
• Instrumented unit tests => medium tests
• Medium tests => UI tests
• Large Tests => User Scenario Tests

Toolset is also very similar, especially using  Espresso Intents to simplify and focus on functional tests for each view. Large Tests / User Scenario Tests by Appium or UiAutomator, too. Truth based assertion also. (I used assertj before, but I betted to Truth because I faced test not found errors in Android environment with the assertj.)

I’m happy to see my belief for mobile test automation design strategy has been going the proper way.

BTW, Appium also supports tests for app bundles. http://appium.io/docs/en/writing-running-appium/android/android-appbundle/