Trade entry price not as expected

[CadeHalcyon]

I am new to backtester.py and am trying out trade entries to see how they materialise, and currently they are not as expected. I wrote the following code:

`
def next (self):

    Wf_Top = self.wf_Top  
    Wf_Low = self.wf_Low `
    
    if not self.position:
        if self.data.Close[-1] > Wf_Top[-1]: 
            self.sell()
    else:
        if self.data.Close[-1] < Wf_Low[-1]: 
            self.position.close()`

Note: Wf_Top is the blue lambda line on the chart in the pic below:

My intention was for a sell trade to be entered above the blue line on the chart, however, the trade was entered well below the blue line, and also at a price point that doesn't even exist at the time the trade was entered (it is below any candlesticks). Grateful for any help with this. Thanks.

[kernc]

I suppose you were unable to check the FAQ.

It's got to do with Backtest(..., commission=...). See e.g.: #633 #538

[CadeHalcyon]

Thanks