Backtesting made Easy: Buy and Hold Strategy with Backtrader

# install requirement
%pip install backtrader yfinance matplotlib

# import libs
import datetime
import backtrader as bt
import yfinance as yf
import matplotlib.pyplot as plt

## ticker and ratio
TICKERS = {"VTI": 0.4, "BND": 0.4, "GLD": 0.2}
## start date and end date
FROMDATE = datetime.datetime(2014, 7, 1)
TODATE = datetime.datetime(2024, 7, 1)

# Definition of Buy and Hold strategy
class BuyAndHold(bt.Strategy):
    def __init__(self):
        pass
    def next(self):
        if not self.position:
            for data in self.datas:
                allocation= data.target
                cash_for_asset = self.broker.get_cash() * allocation
                self.buy(data=data, size=int(cash_for_asset // data.close[0]))

# Initialization of backtrader
cerebro = bt.Cerebro()
cerebro.broker.set_cash(10000)
cerebro.addstrategy(BuyAndHold)
# Read data from yahoofinance
for ticker, target in TICKERS.items():
    data = bt.feeds.PandasData(
        dataname=yf.download(ticker, start=FROMDATE, end=TODATE)
    )
    data.target = target
    cerebro.adddata(data, name=ticker)
# Execution of backtest
print('Starting Portfolio Value: %.2f' % cerebro.broker.getvalue())
cerebro.run()
print('Final Portfolio Value: %.2f' % cerebro.broker.getvalue())

Starting Portfolio Value: 10000.00
Final Portfolio Value: 17274.97

plt.rcParams['figure.figsize'] = [12, 10]
cerebro.plot()