问带有可空类型的Delphi模拟

EN

program DSharkMockNullable;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  DSharp.Testing.Mock,
  Spring,
  System.SysUtils;

type

  {$M+}
  IBaseMock = interface
  ['{B3311345-3C1F-47E3-8235-57B1BA04E957}']
    function GetId:  TNullableInteger;
    procedure SetId(Value: TNullableInteger);
    property Id: TNullableInteger read GetId write SetId;
  end;

  {$M+}
  IMockMe = interface(IBaseMock)
  ['{07F8F233-E8F5-4743-88C5-97A66BB01E29}']
    function GetObjectId:  TNullableInteger;
    procedure SetObjectId(Value: TNullableInteger);
    property ObjectId: TNullableInteger read GetObjectId write SetObjectId;
    function GetObjectName:  TNullableString;
    procedure SetObjectName(Value: TNullableString);
    property ObjectName: TNullableString read GetObjectName write SetObjectName;
  end;

  TMyObject = class
  public
    function ObjectIdAsString(const AObject: IMockMe): string;
  end;


{ TMyObject }

function TMyObject.ObjectIdAsString(const AObject: IMockMe): string;
var
  LId: Integer;
  LObjectId: Integer;
  LObjectName: string;
begin
  LId := AObject.Id;  // ***** FAILS HERE with an "Invalid Typecast" error
  LObjectId := AObject.ObjectId;
  LObjectName := AObject.ObjectName;
  Result := Format('Id: %d', [LId]);
  Result := Format('Object Id: %d', [LObjectId]);
  Result := Format('Object Name: %s', [LObjectName]);
end;

var
  LMock: Mock<IMockMe>;
  LObject: TMyObject;
begin
  try
    LMock.Setup.WillReturn(123).Any.WhenCalling.Id;
    LMock.Setup.WillReturn(456).Any.WhenCalling.ObjectId;
    LMock.Setup.WillReturn('blahblah').Any.WhenCalling.ObjectName;

    LObject := TMyObject.Create;
    Writeln(LObject.ObjectIdAsString(LMock.Instance));
    LObject.Free;

    Readln;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.