text: import Foundation
  
  public enum Expectation: Hashable {
      case value(String)
      case error
  
      public init?(_ string: String?) {
          guard let string = string?.trimmingCharacters(in: .whitespacesAndNewlines) else { return nil }
          if string.starts(with: "=>"),
              let index = string.firstIndex(where: { $0.isWhitespace })
          {
              self = .value(string.suffix(from: index).trimmingCharacters(in: .whitespaces))
          } else if string.starts(with: "!!") {
              self = .error
          } else {
              return nil
          }
      }
  }
  