Add class chain locator type for iOS XCUITest-based driver

[mykola-mokhnach]

Change list

Adds a new class chain locator type for iOS XCUITest-based driver

Types of changes

What types of changes are you proposing/introducing to Java client?
Put an x in the boxes that apply

• No changes in production code.
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Details

This PR is based on appium/appium-xcuitest-driver#391
Class chain locator description and usage examples are present on https://github.com/facebook/WebDriverAgent/wiki/Queries

[mykola-mokhnach]

I'd be very happy if one could provide me with xml source of the app we use for functional iOS testing, so I could add some tests for class chain locator type.

[SrinivasanTarget]

Interesting. @mykola-mokhnach TestApp is available in our repo, you can use the same and add some tests.

[mykola-mokhnach]

Done. Functional tests have been added

[SrinivasanTarget]

cool @mykola-mokhnach Will review in sometime

[SrinivasanTarget]

LGTM 👍 Thanks @mykola-mokhnach

[TikhomirovSergey]

@SrinivasanTarget @mykola-mokhnach this is cool 👍

[TikhomirovSergey]

@SrinivasanTarget Are tests passed? I would like to publish it in BETA6.

[SrinivasanTarget]

Yes @TikhomirovSergey Its a merge away

[himankarbn]

@mykola-mokhnach @SrinivasanTarget: Need some help... So far we have been using XCUITest for our automation. We recently started with Appium Ruby and would like to use class_chain locator type strategy but we are having some trouble with it. Here is a the sample tree of our login screen

In XCTest to get the Password text field we use table.cells.containing(.staticText, identifier:"Password").children(matching: .secureTextField).element

Is there a better/shorter way to find the password field using class_chain ?
find_elements(:class_chain, 'XCUIElementTypeWindow/XCUIElementTypeOther/XCUIElementTypeOther/XCUIElementTypeOther/XCUIElementTypeTable/XCUIElementTypeCell[3]/XCUIElementTypeStaticText')[0]