How to test a combineLatest observable with RxTest? - ios

Question

So I have this viewModel which has a validation observable that is simply the combination of 5 other signals into a boolean.
import RxSwift
class SchedulingFormViewModel: BaseViewModel {
let places = Variable<[String]>([])
var formIsValid: Observable<Bool>!
override init() {
super.init()
places.value = ["LUGAR 1", "LUGAR 2", "LUGAR 3"]
formIsValid = Observable.combineLatest(UserSession.currenctScheduling.dateSignal.asObservable(),
UserSession.currenctScheduling.carSignal.asObservable(),
UserSession.currenctScheduling.locationSignal.asObservable(),
UserSession.currenctScheduling.servicesSignal.asObservable())
{ (date: Date?, car: Car?, location: String?, services: [Service]?) in
print("DATE: \(date), CAR: \(car), LOCATION: \(location), SERVICES:\(services)")
guard let servicesArray = services else { return false }
let valid = date != nil && car != nil && location != nil && servicesArray.count > 0
return valid
}
}
}
And then I have my test class with a method that should just test whether the signal changes or not. I've tried a variety of approaches but none of them really gets the true value at the end. The observable only emits a true signal after the test has run.
My test class is setup like this
import XCTest
import RxSwift
import RxTest
#testable import Automobi
class SchedulingUnitTests: XCTestCase {
var viewModel: SchedulingFormViewModel!
var disposeBag: DisposeBag!
var scheduler: TestScheduler!
override func setUp() {
super.setUp()
viewModel = SchedulingFormViewModel()
UserSession.clearScheduling()
disposeBag = DisposeBag()
scheduler = TestScheduler(initialClock: 0)
}
}
I've tried the TestScheduler
func testFormValidation() {
UserSession.currenctScheduling.dateSignal.value = Date()
UserSession.currenctScheduling.carSignal.value = Car()
UserSession.currenctScheduling.servicesSignal.value = [Service(), Service()]
let location = scheduler.createHotObservable([
next(100, "TEST")
])
location.subscribe(onNext: { (text) in
print("LOCATION: \(text)")
UserSession.currenctScheduling.locationSignal.value = text
}).addDisposableTo(disposeBag)
let results = scheduler.createObserver(Bool.self)
scheduler.scheduleAt(0) {
self.viewModel.formIsValid.subscribe(results).addDisposableTo(self.disposeBag)
}
let expected = [
next(100, true)
]
scheduler.start()
XCTAssertEqual(results.events, expected)
}
Also
func testFormValidation() {
UserSession.currenctScheduling.dateSignal.value = Date()
UserSession.currenctScheduling.carSignal.value = Car()
UserSession.currenctScheduling.servicesSignal.value = [Service(), Service()]
let location = scheduler.createHotObservable([
next(100, "TEST"),
next(150, "TEST 2"),
next(200, "TEST 3")
])
location.subscribe(onNext: { (text) in
print("LOCATION: \(text)")
UserSession.currenctScheduling.locationSignal.value = text
}).addDisposableTo(disposeBag)
var results = [Bool]()
viewModel.formIsValid.subscribe(onNext: { (value) in
results.append(value)
}).addDisposableTo(disposeBag)
let expected = [true, true, true]
scheduler.start()
XCTAssertEqual(results, expected)
}
I've tried things like binding my formIsValid to a Variable and verifying its value at the end.
func testFormValidation() {
UserSession.currenctScheduling.dateSignal.value = Date()
UserSession.currenctScheduling.carSignal.value = Car()
UserSession.currenctScheduling.locationSignal.value = "TESTE"
UserSession.currenctScheduling.servicesSignal.value = [Service(), Service()]
sleep(5)
XCTAssertTrue(viewModel.formIsValid.value)
}
But I never get the expected result. I do get a true signal after all the tests fail and the code goes back to executing. Also when running the app the code executes as expecte I just need to catch it in the test. Any ideas?!

Answer 1

On your first try, you are probably getting a value on clock 0, so your expected value should be:
let expected = [
next(0, false)
next(100, true)
]