public async Task AccountExist_Get_WhenAccountExist()
        {
            //arrange
            var IdTo = 3;

            var loggerMock   = new Mock <ILogger <OperationController> >();
            var accountMock  = new Mock <IAsyncRepository <BankAccount> >();
            var mediatorMock = new Mock <IMediator>();

            mediatorMock.Setup(x => x.Send(It.IsAny <CheckAccountExistQuery>(),
                                           It.IsAny <CancellationToken>()))
            .ReturnsAsync(true)
            .Verifiable();

            var controller = new OperationController(mediatorMock.Object, accountMock.Object, loggerMock.Object);

            //act
            var result = await controller.AccountExist(IdTo);

            //assert
            var viewResult = Assert.IsType <JsonResult>(result);

            Assert.True((bool)viewResult.Value);
        }