`Accessible` provides the way to find the element by a consistent name in UI tests.

Accessible.swift

import UIKit

/**
 `Accessible` provides the way to find the element by a consistent name
 in UI tests.

 `generateAccessibilityIdentifiers()` creates the identifier that forms
 the combination of the class name and the property name that is styled
 like "ClassName.propertyName" and sets it to `accessibilityIdentifier`
 to each property that is UIView.

 e.g.
 - `WelcomeViewController.view`
 - `WelcomeViewController.buttonStackView`

 You can conform `Accessible` to your custom `UIViewController` or `UIView`
 and call `generateAccessibilityIdentifiers()` after all view properties
 are initalized like in the last line of `viewDidLoad()` or an initalizer.

**/

public protocol Accessible {
    func generateAccessibilityIdentifiers()
}

public extension Accessible where Self: NSObject {
    func generateAccessibilityIdentifiers() {
        #if DEBUG
            let mirror = Mirror(reflecting: self)
            generateAccessibilityIdentifiers(mirror)
        #endif
    }

    private func generateAccessibilityIdentifiers(_ mirror: Mirror) {
        // If it has no children, we treat the object as objc implementation.
        if mirror.children.isEmpty {
            generateAccessibilityIdentifiersForObjc(mirror)
        } else {
            for child in mirror.children {
                generateAccessibilityIdentifier(for: child)
            }
        }

        if let superclassMirror = mirror.superclassMirror {
            generateAccessibilityIdentifiers(superclassMirror)
        }
    }

    private func generateAccessibilityIdentifier(for child: Mirror.Child) {
        guard let view = child.value as? UIView else { return }
        guard let label = child.label else { return }

        let property = label.replacingOccurrences(of: ".storage", with: "") // lazy vars appends ".storage".
        view.accessibilityIdentifier = "\(type(of: self)).\(property)"
    }

    private func generateAccessibilityIdentifiersForObjc(_ mirror: Mirror) {
        var outCount: UInt32 = 0
        guard let properties = class_copyPropertyList(mirror.subjectType as? AnyClass, &outCount) else { return }

        // swiftlint:disable:next identifier_name
        for i: UInt32 in 0 ..< outCount {
            let property = properties[Int(i)]
            let ignoreProperties = [
                "window", // Weak referenced as the property of a view controller.
                "viewIfLoaded", // `view` has been overridden by this property.
            ]
            if
                let name = property.name(),
                !ignoreProperties.contains(name),
                property.type() is UIView.Type,
                let view = value(forKey: name) as? UIView {
                view.accessibilityIdentifier = "\(type(of: self)).\(name)"
            }
        }
    }
}

private extension objc_property_t {
    func name() -> String? {
        return String(cString: property_getName(self), encoding: .utf8)
    }

    func type() -> AnyClass? {
        guard let attributes = String(cString: property_getAttributes(self)!, encoding: .utf8)
        else { return nil }
        guard let regexp = try? NSRegularExpression(pattern: "T@\"(.*)\"", options: []) else { return nil }

        guard let result = regexp.firstMatch(
            in: attributes,
            options: [],
            range: NSRange(location: 0, length: attributes.count)
        ) else { return nil }

        let range = result.range(at: 1)
        let className = attributes[range]
        return NSClassFromString(className)
    }
}

L95はNSRangeの型なので
Range型にConvertしないと
attributes[range] でコンパイルエラーになります
なので以下のように変更したら動きました。

let range = result.range(at: 1)
if let range = Range(nsRange, in: attributes) {
    attributes[range]
}

環境差異ぽいですが、より新しくはそうですね。コメントありがとうございます！😊

Hello, on iOS13 this protocol throws exception
Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<Project.ViewController 0x7ff2cf714870> valueForUndefinedKey:]: this class is not key value coding-compliant for the key tabBarObservedScrollView.' particularly in line 72. It's strange bc i have only one VC which is not a tabBarVC, it's an empty project and still throws that error. Do you know what might causing this problem, or how to fix it? Btw. thanks for sharing code

EDIT: quick fix between line 72 and 71 name != "tabBarObservedScrollView" and it's working. I think this might be a bug bc tabBarObservedScrollView applies to tvOS 13+ so why it's there idk

Sorry, but, I don't have any idea. I'll try this later on iOS 13.