MVVM-C Coordinator Unit Tests

CountryListCoordinatorTests.swift

import XCTest
@testable import MVVMCDemo

class CountryListCoordinatorTests: XCTestCase {

    private let sut = CountryListCoordinator(requestManager: LocalRequestManager())
    
    func testStart() {
        XCTAssertTrue(sut.start() is CountryListViewController)
    }
    
    func testDidSelectCountry() {
        _ = sut.start()
        let viewController = UIViewControllerMock()
        sut.didSelect(country: dummyContry, in: viewController)
        
        guard let navigationController = viewController.viewControllerToPresent as? UINavigationController else {
            XCTFail("Presented ViewController must be embedded in UINavigationController.")
            return
        }
        
        XCTAssertTrue(navigationController.viewControllers.first is CountryDetailViewController)
    }
    
    func testDidFailLoading() {
        let viewController = sut.start()
        UIApplication.shared.windows.first?.rootViewController = viewController
        
        sut.didFailLoading(error: NSError(domain: "test", code: 100, userInfo: nil))
        
        guard let alert = viewController.presentedViewController as? UIAlertController else {
            XCTFail("Presented ViewController must be UIAlertController.")
            return
        }
        
        XCTAssertEqual(alert.title, "Error")
        XCTAssertEqual(alert.message, "Could not search country for the keyword.")
        XCTAssertEqual(alert.actions.count, 1)
        XCTAssertEqual(alert.actions[0].title, "Ok")
    }

}

private let jsonData: Data = """
{
  "name": "British Indian Ocean Territory",
  "capital": "Diego Garcia",
  "region": "Africa",
  "subregion": "Eastern Africa",
  "timezones": [
    "UTC+06:00"
  ],
  "borders": [],
  "currencies": [
    {
      "code": "USD",
      "name": "United States dollar",
      "symbol": "$"
    }
  ],
  "languages": [
    {
      "iso639_1": "en",
      "iso639_2": "eng",
      "name": "English",
      "nativeName": "English"
    }
  ]
}
""".data(using: .utf8)!

private let dummyContry: Country = try! JSONParser().parseData(data: jsonData)