public void AddAmount_Ok(decimal amountForAdd)
{
// Arrange
var amountOriginal = 5;
var stock = new Stock
{
Id = 1,
ClientId = 1,
ProductId = 1,
Actived = true,
Amount = amountOriginal
};
// Act
stock.AddAmount(amountForAdd);
// Assert
stock.Amount.Should().Be(amountOriginal + amountForAdd);
}