How would I write a test to make sure the UIbutton "Show all Providers" turns up when there's more than 12 or more items in the table view? - swift

Question

So I'm completely new to testing and I just needed some help figuring out for example how I would write a test for each of the three cases in the enum of the View Model (none, dontSeeProvider, showAllProviders).
enum ProvidersButtonType {
case none, dontSeeProvider, showAllProviders
}
I haven't been able to figure out how to write a test for cases "showAllProviders" and "dontSeeProviders".
This is the View Model:
import RxSwift
import RxCocoa
struct TopProvidersPickerItem {
let provider: MVPD
let logoImage: Observable<UIImage>
init(provider: MVPD, imageLoader: DecodableProviding) {
self.init(provider: provider, logoImage: imageLoader.image(fromURL: provider.logoUrl))
}
init(provider: MVPD, logoImage: Observable<UIImage>) {
self.provider = provider
self.logoImage = logoImage.catchErrorJustReturn(UIImage())
}
}
enum ProvidersButtonType {
case none, dontSeeProvider, showAllProviders
}
struct TopProvidersPickerViewModel {
var caption: String {
return "Get access to more full episodes by signing in with your TV Provider"
}
let buttonType = Variable<ProvidersButtonType>(.none)
let items: Observable<[TopProvidersPickerItem]>
let selectedItem: PublishSubject<TopProvidersPickerItem> = PublishSubject()
let showAllProvidersTrigger: PublishSubject<Void> = PublishSubject()
let mvpdPicked: Observable<MVPD>
init(topProviders: Observable<[MVPD]>, imageLoader: DecodableProviding) {
let items = topProviders.map({ mvpds in
return mvpds.map { mvpd in
TopProvidersPickerItem(provider: mvpd, imageLoader: imageLoader)
}
})
self.init(items: items)
}
init(items: Observable<[TopProvidersPickerItem]>) {
self.items = items
mvpdPicked = selectedItem.map { $0.provider }
let buttonType = items.map { (array) -> ProvidersButtonType in
if array.count > 12 {
return .showAllProviders
} else {
return .dontSeeProvider
}
}
buttonType.bind(to: self.buttonType)
}
}
This is the View Controller:
import UIKit
import RxCocoa
import RxSwift
public class ProviderCollectionViewCell: UICollectionViewCell {
#IBOutlet public private(set) weak var imageView: UIImageView!
}
public class TopProvidersPickerViewController: UIViewController,
ViewModelHolder {
var viewModel: TopProvidersPickerViewModel! = nil
private let bag = DisposeBag()
#IBOutlet public private(set) weak var collectionView: UICollectionView!
#IBOutlet public private(set) weak var captionLabel: UILabel!
#IBOutlet weak var viewAllProvidersButton: UIButton!
override public func viewDidLoad() {
super.viewDidLoad()
captionLabel.text = viewModel.caption
setupRx()
}
private func setupRx() {
viewModel.buttonType.asObservable().subscribe(onNext: { [button = self.viewAllProvidersButton] type in
button?.isHidden = false
switch type {
case .none:
button?.isHidden = true
case .dontSeeProvider:
button?.setTitle("Don't see provider", for: .normal)
case .showAllProviders:
button?.setTitle("Show all providers", for: .normal)
}
})
.disposed(by: bag)
viewModel.items
.bind(to: collectionView
.rx
.items(cellIdentifier: "ProviderCell", cellType: ProviderCollectionViewCell.self)) { [ unowned self ] _, item, cell in
item.logoImage.bind(to: cell.imageView.rx.image).addDisposableTo(self.bag)
}
.addDisposableTo(bag)
collectionView
.rx
.modelSelected(TopProvidersPickerItem.self)
.bind(to: self.viewModel.selectedItem)
.addDisposableTo(bag)
viewAllProvidersButton
.rx
.tap
.bind(to: self.viewModel.showAllProvidersTrigger)
.addDisposableTo(bag)
}
}
I wrote a test for the "none" case, but haven't been able to figure out the other two cases:
import FBSnapshotTestCase
import OHHTTPStubs
import RxSwift
#testable import AuthSuite
class TopProvidersPickerViewControllerTests: FBSnapshotTestCase,
ProvidersViewControllerTests {
override func setUp() {
super.setUp()
recordMode = true
}
func testDoesNotShowButtonWhenLoadingProviders() {
let viewModel = TopProvidersPickerViewModel(items: .never())
let controller = TopProvidersPickerViewController.instantiateViewController(with: viewModel)
presentViewController(controller)
FBSnapshotVerifyView(controller.view)
}

Answer 1

I've never used FB Snapshot Tester. I'm going to have to look into that.
Here's how I would do it:
I wouldn't expose the enum to the ViewController. setupRx() would contain this instead:
private func setupRx() {
viewModel.buttonTitle
.bind(to: viewAllProvidersButton.rx.title(for: .normal))
.disposed(by: bag)
viewModel.buttonHidden
.bind(to: viewAllProvidersButton.rx.isHidden)
.disposed(by: bag)
// everything else
}
Then to test the title of the button, for example, I would use these tests:
import XCTest
import RxSwift
#testable import RxPlayground
class TopProvidersPickerViewModelTests: XCTestCase {
func testButtonTitleEmptyItems() {
let topProviders = Observable<[MVPD]>.just([])
let decodableProviding = MockDecodableProviding()
let viewModel = TopProvidersPickerViewModel(topProviders: topProviders, imageLoader: decodableProviding)
var title: String = ""
_ = viewModel.buttonTitle.subscribe(onNext: { title = $0 })
XCTAssertEqual(title, "Don't see provider")
}
func testButtonTitle12Items() {
let topProviders = Observable<[MVPD]>.just(Array(repeating: MVPD(), count: 12))
let decodableProviding = MockDecodableProviding()
let viewModel = TopProvidersPickerViewModel(topProviders: topProviders, imageLoader: decodableProviding)
var title: String = ""
_ = viewModel.buttonTitle.subscribe(onNext: { title = $0 })
XCTAssertEqual(title, "Don't see provider")
}
func testButtonTitle13Items() {
let topProviders = Observable<[MVPD]>.just(Array(repeating: MVPD(), count: 13))
let decodableProviding = MockDecodableProviding()
let viewModel = TopProvidersPickerViewModel(topProviders: topProviders, imageLoader: decodableProviding)
var title: String = ""
_ = viewModel.buttonTitle.subscribe(onNext: { title = $0 })
XCTAssertEqual(title, "Show all providers")
}
}
class MockDecodableProviding: DecodableProviding {
// nothing needed for these tests.
}