EA Studio calculates and applies the swaps to the open positions. It uses the swap related settings that come with the data file.
You may see the particular swaps for the symbol in Data -> Data Statistics page.

These are the current parameters for the EURUSD demo data thata comes with EA Studio:

Swap type       Points
Swap 3 days    Wednesday
Swap long        -12.75
Swap short      6.08

EA Studio applies the Swap by correcting the position's open price. It uses the following formula:

Open_price = Previous_open_price + 0.00001 * Swap

EA Studio will apply the weekend's swap on Wednesday for the current example. Your broker may have different Swap parameters.

i´m not sure about swaps are calculated before the results of profit or not, i.e that they are taken into account or not.

I need to be sure about that because depend on the swaps many strategies will be profitable or not. In the case that the swaps are not included in the calculations it´s ok too because i can put the slippage bigger so that can be compensate and make a good estimation of the general results but i need to know it.

So, my question is, Expert Advisor Studio calculate the total cost of the swaps of the every trade and substract of the net profit result?

Thank you very much