How to use testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed method of ClassUnderTest class

...12            ("testWaitUntilTimesOutIfNotCalled", testWaitUntilTimesOutIfNotCalled),13            ("testWaitUntilTimesOutWhenExceedingItsTime", testWaitUntilTimesOutWhenExceedingItsTime),14            ("testWaitUntilNegativeMatches", testWaitUntilNegativeMatches),15            ("testWaitUntilDetectsStalledMainThreadActivity", testWaitUntilDetectsStalledMainThreadActivity),16            ("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed", testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed),17            ("testWaitUntilErrorsIfDoneIsCalledMultipleTimes", testWaitUntilErrorsIfDoneIsCalledMultipleTimes),18            ("testWaitUntilMustBeInMainThread", testWaitUntilMustBeInMainThread),19            ("testToEventuallyMustBeInMainThread", testToEventuallyMustBeInMainThread),20            ("testSubjectUnderTestIsReleasedFromMemory", testSubjectUnderTestIsReleasedFromMemory),21        ]22    }23    class Error: Swift.Error {}24    let errorToThrow = Error()25    private func doThrowError() throws -> Int {26        throw errorToThrow27    }28    func testToEventuallyPositiveMatches() {29        var value = 030        deferToMainQueue { value = 1 }31        expect { value }.toEventually(equal(1))32        deferToMainQueue { value = 0 }33        expect { value }.toEventuallyNot(equal(1))34    }35    func testToEventuallyNegativeMatches() {36        let value = 037        failsWithErrorMessage("expected to eventually not equal <0>, got <0>") {38            expect { value }.toEventuallyNot(equal(0))39        }40        failsWithErrorMessage("expected to eventually equal <1>, got <0>") {41            expect { value }.toEventually(equal(1))42        }43        failsWithErrorMessage("unexpected error thrown: <\(errorToThrow)>") {44            expect { try self.doThrowError() }.toEventually(equal(1))45        }46        failsWithErrorMessage("unexpected error thrown: <\(errorToThrow)>") {47            expect { try self.doThrowError() }.toEventuallyNot(equal(0))48        }49    }50    func testToEventuallyWithCustomDefaultTimeout() {51        AsyncDefaults.Timeout = 252        defer {53            AsyncDefaults.Timeout = 154        }55        var value = 056        let sleepThenSetValueTo: (Int) -> Void = { newValue in57            Thread.sleep(forTimeInterval: 1.1)58            value = newValue59        }60        var asyncOperation: () -> Void = { sleepThenSetValueTo(1) }61        if #available(OSX 10.10, *) {62            DispatchQueue.global().async(execute: asyncOperation)63        } else {64            DispatchQueue.global(priority: .default).async(execute: asyncOperation)65        }66        expect { value }.toEventually(equal(1))67        asyncOperation = { sleepThenSetValueTo(0) }68        if #available(OSX 10.10, *) {69            DispatchQueue.global().async(execute: asyncOperation)70        } else {71            DispatchQueue.global(priority: .default).async(execute: asyncOperation)72        }73        expect { value }.toEventuallyNot(equal(1))74    }75    func testWaitUntilPositiveMatches() {76        waitUntil { done in77            done()78        }79        waitUntil { done in80            deferToMainQueue {81                done()82            }83        }84    }85    func testWaitUntilTimesOutIfNotCalled() {86        failsWithErrorMessage("Waited more than 1.0 second") {87            waitUntil(timeout: 1) { _ in return }88        }89    }90    func testWaitUntilTimesOutWhenExceedingItsTime() {91        var waiting = true92        failsWithErrorMessage("Waited more than 0.01 seconds") {93            waitUntil(timeout: 0.01) { done in94                let asyncOperation: () -> Void = {95                    Thread.sleep(forTimeInterval: 0.1)96                    done()97                    waiting = false98                }99                if #available(OSX 10.10, *) {100                    DispatchQueue.global().async(execute: asyncOperation)101                } else {102                    DispatchQueue.global(priority: .default).async(execute: asyncOperation)103                }104            }105        }106        // "clear" runloop to ensure this test doesn't poison other tests107        repeat {108            RunLoop.main.run(until: Date().addingTimeInterval(0.2))109        } while(waiting)110    }111    func testWaitUntilNegativeMatches() {112        failsWithErrorMessage("expected to equal <2>, got <1>") {113            waitUntil { done in114                Thread.sleep(forTimeInterval: 0.1)115                expect(1).to(equal(2))116                done()117            }118        }119    }120    func testWaitUntilDetectsStalledMainThreadActivity() {121        let msg = "-waitUntil() timed out but was unable to run the timeout handler because the main thread is unresponsive (0.5 seconds is allow after the wait times out). Conditions that may cause this include processing blocking IO on the main thread, calls to sleep(), deadlocks, and synchronous IPC. Nimble forcefully stopped run loop which may cause future failures in test run."122        failsWithErrorMessage(msg) {123            waitUntil(timeout: 1) { done in124                Thread.sleep(forTimeInterval: 5.0)125                done()126            }127        }128    }129    func testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed() {130        // Currently we are unable to catch Objective-C exceptions when built by the Swift Package Manager131#if !SWIFT_PACKAGE132        let referenceLine = #line + 9133        var msg = "Unexpected exception raised: Nested async expectations are not allowed "134        msg += "to avoid creating flaky tests."135        msg += "\n\n"136        msg += "The call to\n\t"137        msg += "expect(...).toEventually(...) at \(#file):\(referenceLine + 7)\n"138        msg += "triggered this exception because\n\t"139        msg += "waitUntil(...) at \(#file):\(referenceLine + 1)\n"140        msg += "is currently managing the main run loop."141        failsWithErrorMessage(msg) { // reference line142            waitUntil(timeout: 2.0) { done in143                var protected: Int = 0...

1ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()2ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()3ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()4ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()5ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()6ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()7ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()8ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()9ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()10ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()11ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()12ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()

1let classUnderTest = ClassUnderTest()2classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()3let classUnderTest = ClassUnderTest()4classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()5let classUnderTest = ClassUnderTest()6classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()7let classUnderTest = ClassUnderTest()8classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()9let classUnderTest = ClassUnderTest()10classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()11let classUnderTest = ClassUnderTest()12classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()

1let classUnderTest = ClassUnderTest()2classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()3let classUnderTest = ClassUnderTest()4classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()5    "Test case failed (waited too long for 6    UserInfo={NSLocalizedDescription=Test case failed (waited too long for 7    expectation "TestCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed")}: file 8    "Test case failed (waited too long for 9    UserInfo={NSLocalizedDescription=Test case failed (waited too long for 10    expectation "TestCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed")}: file 

1let classUnderTest = ClassUnderTest()2classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()3let classUnderTest = ClassUnderTest()4classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()5let classUnderTest = ClassUnderTest()6classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()7let classUnderTest = ClassUnderTest()8classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()9let classUnderTest = ClassUnderTest()10classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()11let classUnderTest = ClassUnderTest()12classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()13let classUnderTest = ClassUnderTest()14classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()15let classUnderTest = ClassUnderTest()16classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()17let classUnderTest = ClassUnderTest()18classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()19let classUnderTest = ClassUnderTest()20classUnderTest.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()21let classUnderTest = ClassUnderTest()

1let sut = ClassUnderTest()2sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()3let sut = ClassUnderTest()4sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()5let sut = ClassUnderTest()6sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()7let sut = ClassUnderTest()8sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()9let sut = ClassUnderTest()10sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()11let sut = ClassUnderTest()12sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()13let sut = ClassUnderTest()14sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()15let sut = ClassUnderTest()

1import XCTest2import Quick3import Nimble4@testable import ClassUnderTest5class ClassUnderTestSpec: QuickSpec {6    override func spec() {7        describe("ClassUnderTest") {8            it("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed") {9                let sut = ClassUnderTest()10                sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()11            }12        }13    }14}15import Foundation16import XCTest17import Nimble18class ClassUnderTest {19    func testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed() {20        DispatchQueue.global().async {21        }22        waitUntil { done in23            DispatchQueue.global().asyncAfter(deadline: .now() + 0.1) {24                done()25            }26        }27        expect(value).toEventually(equal(1))28    }29}30import XCTest31import Quick32import Nimble33@testable import ClassUnderTest34class ClassUnderTestTests: XCTestCase {35    func testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed() {36        let sut = ClassUnderTest()37        sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()38    }39}40I think the problem is that you're using waitUntil() in a test that's already marked as async. You should be able to replace the test with the following:41func testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed() {42    let sut = ClassUnderTest()43    DispatchQueue.global().async {44    }45    waitUntil { done in46        DispatchQueue.global().asyncAfter(deadline: .now() + 0.1) {47            done()48        }49    }50    expect(value).toEventually

1import Quick2import Nimble3class ClassUnderTestSpec: QuickSpec {4    override func spec() {5        describe("ClassUnderTest") {6            beforeEach {7                sut = ClassUnderTest()8            }9            it("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed") {10                sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()11            }12        }13    }14}15import Quick16import Nimble17class ClassUnderTestSpec: QuickSpec {18    override func spec() {19        describe("ClassUnderTest") {20            beforeEach {21                sut = ClassUnderTest()22            }23            it("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed") {24                sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()25            }26        }27    }28}29import Quick30import Nimble31class ClassUnderTestSpec: QuickSpec {32    override func spec() {33        describe("ClassUnderTest") {34            beforeEach {35                sut = ClassUnderTest()36            }37            it("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed") {38                sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()39            }40        }41    }42}43import Quick44import Nimble45class ClassUnderTestSpec: QuickSpec {46    override func spec() {47        describe("ClassUnderTest") {48            beforeEach {49                sut = ClassUnderTest()50            }51            it("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed") {52                sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()53            }54        }55    }56}57import Quick58import Nimble59class ClassUnderTestSpec: QuickSpec {60    override func spec() {61        describe("ClassUnderTest") {

1ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()2ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()3ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()4ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()5ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()6ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()7ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()8ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()9ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()10ClassUnderTest().testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()

1import Quick2import Nimble3import XCTest4class ClassUnderTestSpec : QuickSpec {5    override func spec() {6        describe("ClassUnderTest") {7            beforeEach {8                sut = ClassUnderTest()9            }10            it("testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed") {11                sut.testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed()12            }13        }14    }15}16import Quick17import Nimble18import XCTest19class ClassUnderTest {20    func testCombiningAsyncWaitUntilAndToEventuallyIsNotAllowed() {21        asyncOperation { value = $0 }22        waitUntil { done in23            expect(value).toEventually(equal(1))24        }25    }26    private func asyncOperation(completion: @escaping (Int) -> Void) {27        DispatchQueue.global().asyncAfter(deadline: .now() + 0.5) {28            completion(1)29        }30    }31}