Using XCTestObservation to count up failed tests and skip remaining tests when there are too many

xctestobservation.swift

import XCTest

/// Observes test failures and suggests skipping remaining tests when too many have failed
class TestObserver: NSObject {
    
    static let shared = TestObserver()
    
    /// The number of failed tests before the observer will report that remaining tests should be skipped.
    /// This allows test runs to be cut short if numerous tests are failing, indicating an environment issue that's pointless to battle on against.
    private let failureTolerance: UInt
    private var issueCount: UInt = 0
    
    var shouldSkipAllTests: Bool {
        issueCount >= failureTolerance
    }
    
    init(tolerance: UInt = 20) {
        failureTolerance = tolerance
        super.init()
        XCTestObservationCenter.shared.addTestObserver(self)
    }
    
    deinit {
        XCTestObservationCenter.shared.removeTestObserver(self)
    }
        
}

extension TestObserver: XCTestObservation {
    
    func testCase(_ testCase: XCTestCase,
                  didRecord issue: XCTIssue) {
        issueCount += 1
        //print("Test \(testCase) recorded issue: \(issue)")
    }
    
}