How to test a function that make AWSMobileClient request in swift

I have a function

final class API {
  func forgotPassword(
    username: String
  ) -> Future<ConfirmationStatus, Never> {
    Future { _ in
      AWSMobileClient.default().forgotPassword(
        username: username
      ) { forgotPasswordResult, error in
        if let forgotPasswordResult = forgotPasswordResult {
          switch forgotPasswordResult.forgotPasswordState {
          case .confirmationCodeSent:
            // show an alert to a user here
            break
          default:
            logger.error("Error: Invalid case.")
          }
        } else if let error = error {
          logger.error("Error occurred: \(error.localizedDescription)")
        }
      }
    }.onFailure {
      logger.error($0)
    }
  }
}

that will be called when a user tap on a button. I want to test it. I understand in general how should I test it. I should create a function that will be called instead of AWSMobileClient.default().forgotPassword() and it I should use it in forgotPassword test. It might be function in a extension on a protocol. And AWSMobileClient should conform to this protocol.

How should I test API.forgotPassword?

I used BrightFuture to make asynchronous requests.