Waiting for XCUIElement attributes

XCUIElement+waitPredicate.swift

// Source: https://medium.com/@anthony.prokuda/how-to-locate-and-wait-for-an-element-in-xcuitest-a-powerful-approach-105b81628986

extension XCUIElement {
    func wait<U>(
        attribute keyPath: KeyPath<XCUIElement, U>,
        is comparisonOperator: NSComparisonPredicate.Operator,
        value: U,
        timeout: TimeInterval = 10
    ) -> XCUIElement? {
        
        let predicate = NSPredicate.keyPath(
            keyPath,
            is: comparisonOperator,
            value: value
        )
        
        let expectation = XCTNSPredicateExpectation(predicate: predicate, object: self)
        let result = XCTWaiter.wait(for: [expectation], timeout: timeout)
        return result == .completed ? self : nil
    }
}

let progressLabel = app.staticTexts["PROGRESS_LABEL"].firstMatch.wait(attribute: \.label, is: .equalTo, value: "100%")