public async Task Update()
{
var command = new UpdatePartnerCommand()
{
Id = 123
};
_mockMediator.Setup(x => x.Send(command, It.IsAny <CancellationToken>()))
.Returns(Task.FromResult(Unit.Value));
var result = await _sut.Update(command.Id, command);
_mockMediator.Verify(x => x.Send(command, It.IsAny <CancellationToken>()),
Times.Once);
}