             waitForExpectations(timeout: 1.0, handler: nil)
         }
 
-        @available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
         func testItReturnsParsedErrorsCorrectlyUsingAPublisher() {
+            guard #available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *, *) else { return }
             stubRequest(statusCode: 400) { (request) -> Bool in
                 return request.url! == testURL && request.httpMethod == "GET"
             }

            expect(customError).to(equal(CustomError.error))
        }

        @available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
        func testItIncrementsTheActivityMonitorCorrectly() {
            let stubMonitor = SessionActivityMonitor(initialValue: 0, isAsynchronous: false)
            stubRequest(passingTest: { $0.url! == testURL && $0.httpMethod == "GET" })
            var isCurrentlyActive: Bool = false

            expect(isCurrentlyActive).to(beFalse())
        }

        func testItDecrementsTheActivityMonitorCorrectlyOnSessionErrors() {
            guard #available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *, *) else { return }
            let stubMonitor = SessionActivityMonitor(initialValue: 0, isAsynchronous: false)
            session.activityMonitor = stubMonitor
            let testError = NSError(domain: NSURLErrorDomain, code: NSURLErrorCancelled, userInfo: nil)
