Strategy wont execute if the 'cash' is below asset price (e.g. BTC is 60k and starting cash is 1k)

[ch4meleon]

Expected Behavior

Should allow to execute the strategy and allow the calculation in the final stats.

Steps to Reproduce

...
bt = Backtest(df, Test, cash=1000, commission=.002)
stats = bt.run()
print(stats)
...

[kernc]

Backtesting doesn't support fractional units. When the price is higher than starting cash, a warning is issued:

backtesting.py/backtesting/backtesting.py

Lines 1073 to 1077 in 267d99f

	if np.any(data['Close'] > cash):
	warnings.warn('Some prices are larger than initial cash value. Note that fractional '
	'trading is not supported. If you want to trade Bitcoin, '
	'increase initial cash, or trade μBTC or satoshis instead (GH-134).',
	stacklevel=2)

It seems sufficient.

See #134 for a workaround to trade BTC.