FollowerViewModelTest.pt2.swift

class FollowerViewModelTest: XCTestCase {
  let disposeBag = DisposeBag()
  func testFollowersUpdate() {
    let testFollower = User()
    let mockNetworking = FollowerNetworkingMock(mockFollowers: [testFollower])
    // Create a scheduler that starts at 0
    let scheduler = TestScheduler(initialClock: 0)
    let viewModel = FollowUserViewModel(networkHandler: mockNetworking, scheduler: scheduler)
    let testCountObserver = scheduler.createTestObserver(Int.self)
    let testLatestFollowObserver = scheduler.createTestObserver(User.self)
    // Bind just like we did with our subject
    viewModel
      .followCount
      .bind(to: testCountObserver)
      .dispose(by: disposeBag)
    viewModel
      .latestFollow
      .bind(to: testLatestFollowObserver)
      .dispose(by: disposeBag)
    viewModel.followUserObserver.onNext(testFollower)

    scheduler.start()
    // ensure we only got 1 event
    XCTAssertEqual(testCountObserver.events.count, 1)
    // ensure our only event was the Int 1, the number of followers we have
    XCTAssertEqual(testCountObserver.events[0].value.element!, 1)
    // ensure we only got 1 event
    XCTAssertEqual(testLatestFollowObserver.events.count, 1)
    // ensure the follower we got was the same follower we put in our mock
    XCTAssertEqual(testLatestFollowObserver.events[0].value.element!, testFollower)
  }
}