Capturing multiple values in mocks
Basics article available: Unit TestingWhen capturing values in mocks, using an array (instead of just a single value) makes it easy to verify that only a certain number of values were passed.
Perfect for protecting against "over-calling" something.
class UserManagerTests: XCTestCase {
func testObserversCalledWhenUserFirstLogsIn() {
let manager = UserManager()
let observer = ObserverMock()
manager.addObserver(observer)
// First login, observers should be notified
let user = User(id: 123, name: "John")
manager.userDidLogin(user)
XCTAssertEqual(observer.users, [user])
// If the same user logs in again, observers shouldn't be notified
manager.userDidLogin(user)
XCTAssertEqual(observer.users, [user])
}
}
private extension UserManagerTests {
class ObserverMock: UserManagerObserver {
private(set) var users = [User]()
func userDidChange(to user: User) {
users.append(user)
}
}
}
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