Discussion of article "Library for easy and quick development of MetaTrader programs (part XXV): Handling errors returned by the trade server"

In the last MetaTrader 5 versions (starting from the build 2201), the tester features the ability to set parameters of a symbol the test is performed on. Thus, it is possible to set trading limitations on a symbol and test the library behavior when the symbol limitations are detected.

To call the symbol settings window, click the button to the right of the tested timeframe selection:

Allow opening long positions only for a symbol and set the volume limitation of simultaneously opened positions and placed pending orders in one direction to 0.5.

Thus, we will be able to use long positions only and have the maximum total volume of buy positions and orders of no more than 0.5 lot in the market. In other words, when opening a position with the lot of 0.1, we are able to open five positions only or place a single pending buy order and open four positions:

For more authenticity, we could disable auto closure of positions when a specified profit is exceeded. However, we can see that we were unable to open a short position and received the warning that only buy positions are allowed on a symbol. Further on, when trying to open a number of positions with their total volume exceeding 0.5 lots, we receive the message of the inability to open a position due to exceeding the maximum total volume of positions and orders in one direction.