NotificationTests.swift

import XCTest

class MockedNotificationScheduler: NotificationScheduler {
  struct Notification: Equatable {
    let title: String
  }
  
  var scheduledNotifications: [Notification] = []
  
  func scheduleNotification(with title: String) {
    self.scheduledNotifications.append(Notification(title: title))
  }
}

class TimeProviderStub: TimeProvider {
  let now: Date
  let calendarClosure: (Calendar.Identifier) -> Calendar
  
  func calendar(with identifier: Calendar.Identifier) -> Calendar {
    return calendarClosure(identifier)
  }
}

class TestNotificationManager: XCTestCase {
  var notificationScheduler: MockedNotificationScheduler!
  var timeProvider: TimeProvider!
  
  func setUp() {
    super.setUp()
    self.notificationScheduler = MockedNotificationScheduler()
  }
  
  func testMorningNotification_before11_notificationIsScheduled() {
    let timeProvider = TimeProviderStub(
      date: DateComponents(hour: 10).date!, 
      calendarClosure: { id in return Calendar(identifier: id))
    }
    let notificationManager = NotificationManager(
      notificationScheduler: self.notificationScheduler,
      timeProvider: timeProvider
    )
    
    notificationManager.scheduleMorningNotification()
    
    XCTAssertEqual(self.notificationScheduler.scheduledNotifications.count, 1)
    XCTAssertEqual(self.notificationScheduler.scheduledNotifications[0].title, "Good Morning!")
  }
  
    func testMorningNotification_after11_notificationIsNotScheduled() {
    let timeProvider = TimeProviderStub(
      date: DateComponents(hour: 12).date!, 
      calendarClosure: { id in return Calendar(identifier: id))
    }
    let notificationManager = NotificationManager(
      notificationScheduler: self.notificationScheduler,
      timeProvider: timeProvider
    )
    
    notificationManager.scheduleMorningNotification()
    
    XCTAssertEqual(self.notificationScheduler.scheduledNotifications.count, 0)
  }
  
  // ... tests for the other methods
}