A backtester (backtest helper) for testing my trading strategies.
It requires a lot of manual processing and coding. Difficult to comprehend. I tried to explain the use of the library with examples as best I could. But writing such automation is quite complex. There may still be errors. It is pretty difficult to check but I'm trying to improve the usage.
# Testwise is a backtester library that requires some coding knowledge
# There is no cli or interface.
# You should directly execute necessary functions like enter_long() or exit_short()
# This is a backtesting example of Exponential Moving Average cross strategy.
# There is a 1.5 ATR stop loss level and a 1 ATR take profit level for every position.
# Commission rate is 0.1000%.
# Margin usage is allowed up to 5 times the main capital.
from datetime import datetime, timedelta
from testwise import Testwise
import requests
from legitindicators import ema, atr
# In this example, daily BTCUSDT kline data is used from binance
# Let's say you want to backtest your strategy for about 450 days.
# It would be useful to add some extra days to the specified time interval
# for the indicators to work properly.
# (For example 10 days of EMA won't be calculated for the first 9 days of time range)
# In this example I add 40 extra days. This value can be determined by assigning the TRIM variable
TRIM = 40
BINANCE_URL = "https://api.binance.com/api/v3/klines"
SYMBOL = "BTCUSDT"
INTERVAL = "1d"
# These are the initial paramters for backtester.
# You can find a more detailed explanation where the Testwise definition is given below.
COMMISSION = 0.001
DYNAMIC_POSITIONING = True
MARGIN_FACTOR = 5
LIMIT_FACTOR = 1
RISK_FACTOR = 1.5
def main():
# Here we define the start time and end time of backtesting.
# Notice usage of TRIM variable to start to backtest a few days earlier for proper indicator use.
start_time = datetime(2020, 6, 1, 0, 0, 0)
start_time = start_time - timedelta(days=TRIM)
end_time = datetime(2021, 9, 1, 0, 0, 0)
# In this example, timestamps are used. (Because binance accept timestamp)
start_time_ts = int(datetime.timestamp(start_time) * 1000)
end_time_ts = int(datetime.timestamp(end_time) * 1000)
backtest(start_time_ts, end_time_ts)
def backtest(start_time, end_time):
# Getting OHLC data
# Example binance kline response
# [
# [
# 1499040000000, // Open time
# "0.01634790", // Open
# "0.80000000", // High
# "0.01575800", // Low
# "0.01577100", // Close
# "148976.11427815", // Volume
# 1499644799999, // Close time
# "2434.19055334", // Quote asset volume
# 308, // Number of trades
# "1756.87402397", // Taker buy base asset volume
# "28.46694368", // Taker buy quote asset volume
# "17928899.62484339" // Ignore.
# ]
# ]
params = {"symbol": SYMBOL, "interval": INTERVAL, "startTime": start_time, "endTime": end_time}
data = get_data(params)
opn, high, low, close = get_ohlc(data)
# Again for proper indicator usage number of bars to work on is defined as lookback
lookback = len(data) - TRIM
# These are simply trimmed OHLC data
data = data[-lookback:]
# Here, a list of close prices kept under different naming conventions than other OHL data
# That is because I will use this close data as a parameter
# for Exponential Moving Average indicator and then trim the list of EMA values afterward.
close_tmp = close[-lookback:]
opn = opn[-lookback:]
high = high[-lookback:]
low = low[-lookback:]
# Here is the calculation of ATR values historically. I use legitindicators library.
atr_input = []
for i, _ in enumerate(data):
ohlc = [opn[i], high[i], low[i], close_tmp[i]]
atr_input.append(ohlc)
atrng = atr(atr_input, 14)
# Backtesting operation starts here.
# Following two for loops will check two EMA crosses in the range of 10 to 30
for ema_length1 in range(10, 11):
for ema_length2 in range(ema_length1 + 1, 30):
# When the dynamic_positioning is set to True,
# the backtester will work as if the margin usage is available for use.
# margin_factor indicates the margin ratio. (In this example, it is 5 times the main capital)
# limit_factor is an ATR based take profit level. (it is 1 ATR from the position price)
# risk_factor is an ATR based stop loss level. (it is 1.5 ATR from the position price)
twise = Testwise(
commission=COMMISSION,
dynamic_positioning=DYNAMIC_POSITIONING,
margin_factor=MARGIN_FACTOR,
limit_factor=LIMIT_FACTOR,
risk_factor=RISK_FACTOR
)
# Here, two EMA indicators are defined. I use legitindicators library.
ema_first = ema(close, ema_length1)
ema_second = ema(close, ema_length2)
# List of indicator values trimmed accordingly
ema_first = ema_first[-lookback:]
ema_second = ema_second[-lookback:]
# Notice that at this point:
# open, high, low, close, ema_first and ema_second lists are all trimmed
# and all have the same length
# Ready for testing
# Start walking on the data taken from the binance.
for i, _ in enumerate(data):
# Exclude first price data
if i > 1 and i < len(data) - 1:
# Here, data[n][0] is the open time of price data
# date_open is kept for use if there will be a pose to be opened the next day
# date_close is kept for use if the current open position is closed in this iteration
date_open = datetime.fromtimestamp(int(data[i+1][0] / 1000)).strftime("%Y-%m-%d %H")
date_close = datetime.fromtimestamp(int(data[i][0] / 1000)).strftime("%Y-%m-%d %H")
# Position exits
# On every iteration, position exits checked firstly
# Below, if the current position is long (1 means long) and
# the ema_first crosses below the ema_second, position exit function triggered
if twise.pos == 1 and (ema_first[i] < ema_second[i]):
# exit_long function takes closing date,
# closing price as open price of next day opn[i + 1],
# and amount to close the position.
# This amount already kept in twise.current_open_pos["qty"].
# This value is set when opening the positions
twise.exit_long(date_close, opn[i + 1], twise.current_open_pos["qty"])
# Closing short position(-1 means short)
if twise.pos == -1 and (ema_first[i] > ema_second[i]):
twise.exit_short(date_close, opn[i + 1], twise.current_open_pos["qty"])
# The following if condition simulates price movements inside the bar.
# This is crucial if you want to add take profit and stop loss logic to the backtester.
# This pine script broker emulator documentation will explain this condition more clearly:
# https://www.tradingview.com/pine-script-docs/en/v5/concepts/Strategies.html?highlight=strategy#broker-emulator
if abs(high[i] - opn[i]) < abs(low[i] - opn[i]):
# Simply, If the bar’s high is closer to bar’s open than the bar’s low,
# bar movement will be like:
# open - high - low - close
# In this movement, take profit operation will be checked before stop loss.
# This is because, it is assumed that the price will go up first.
# For example, if both take profit and stop loss prices are exceeded,
# it is assumed that first, take profit is taken, than stop loss price is reached.
# if current position is long, here is take profit logic:
# if current position is long and high is
# higher than take proift price (twise.current_open_pos["tp"])
# and take profit is not taken (twise.current_open_pos["tptaken"] is False)
if twise.pos == 1 and high[i] > twise.current_open_pos["tp"] and twise.current_open_pos["tptaken"] is False:
# Stop loss price will be set to break even with break_even() function
twise.break_even()
# Take profit operation is simply a partially position closing operation.
# Here, half of the position is closed. (twise.current_open_pos["qty"] / 2)
twise.exit_long(date_close, twise.current_open_pos["tp"], twise.current_open_pos["qty"] / 2, True)
# if current position is long, here is stop loss logic:
# if current position is long and low is
# lower than stop loss price (twise.current_open_pos["sl"])
if twise.pos == 1 and low[i] < twise.current_open_pos["sl"]:
twise.exit_long(date_close, twise.current_open_pos["sl"], twise.current_open_pos["qty"])
# if current position is short, here is take profit logic:
if twise.pos == -1 and high[i] > twise.current_open_pos["sl"]:
twise.exit_short(date_close, twise.current_open_pos["sl"], twise.current_open_pos["qty"])
# if current position is short, here is stop loss logic:
if twise.pos == -1 and low[i] < twise.current_open_pos["tp"] and twise.current_open_pos["tptaken"] is False:
twise.break_even()
twise.exit_short(date_close, twise.current_open_pos["tp"], twise.current_open_pos["qty"] / 2, True)
else:
# If the bar’s low is closer to bar’s open than the bar’s high,
# bar movement will be like:
# open - low - high - close
# In this movement, stop loss operation will be checked before take profit.
# This is because, it is assumed that the price will go down firstly.
# For example, if both take profit and stop loss prices are exceeded,
# it is assumed that first, stop loss is executed,
# then take profit will never be reached because
# if the position is fully closed with exit_long,
# twise.pos value will be 0 (which means there is no open position).
# if the current position is long, here is stop loss logic:
if twise.pos == 1 and low[i] < twise.current_open_pos["sl"]:
twise.exit_long(date_close, twise.current_open_pos["sl"], twise.current_open_pos["qty"])
# if current position is long, here is take profit logic:
if twise.pos == 1 and high[i] > twise.current_open_pos["tp"] and twise.current_open_pos["tptaken"] is False:
twise.break_even()
twise.exit_long(date_close, twise.current_open_pos["tp"], twise.current_open_pos["qty"] / 2, True)
# if current position is short, here is take profit logic:
if twise.pos == -1 and low[i] < twise.current_open_pos["tp"] and twise.current_open_pos["tptaken"] is False:
twise.break_even()
twise.exit_short(date_close, twise.current_open_pos["tp"], twise.current_open_pos["qty"] / 2, True)
# if current position is short, here is stop loss logic:
if twise.pos == -1 and high[i] > twise.current_open_pos["sl"]:
twise.exit_short(date_close, twise.current_open_pos["sl"], twise.current_open_pos["qty"])
# Opening long position
# If there is no long positions open
if twise.pos != 1:
# If ema_first crosses over ema_second
if ema_first[i] > ema_second[i]:
# You can manually set the amount to open position.
# But there will be a calculation overhead.
# Testwise has a built-in share calculation funciton
# In tihs function, share is calculated as:
# share = (equity * position risk) / (atr * risk factor)
share = twise.calculate_share(atrng[i], custom_position_risk=0.02)
# Opening long position with opening date (date_open),
# opening price of next day (opn[i + 1]),
# amount to buy, and current atr value to define take profit and stop loss prices
twise.entry_long(date_open, opn[i + 1], share, atrng[i])
if twise.pos != -1:
if ema_first[i] < ema_second[i]:
share = twise.calculate_share(atrng[i], custom_position_risk=0.02)
# Opening short position with opening date (date_open),
# opening price of next day (opn[i + 1]),
# amount to buy, and current atr value to define take profit and stop loss prices
twise.entry_short(date_open, opn[i + 1], share, atrng[i])
# get_result() function will give you the backtest results
print(twise.get_result())
def get_data(params):
r = requests.get(url=BINANCE_URL, params=params)
data = r.json()
return data
def get_ohlc(data):
opn = [float(o[1]) for o in data]
close = [float(d[4]) for d in data]
high = [float(h[2]) for h in data]
low = [float(lo[3]) for lo in data]
return opn, high, low, close
if __name__ == "__main__":
main()Example backtest result:
{
'net_profit': 30557.012567638478,
'net_profit_percent': 30.557012567638477,
'gross_profit': 69163.31181062985,
'gross_loss': 36783.34343506002,
'max_drawdown': -13265.365111723615,
'max_drawdown_rate': 2.3035183962356918,
'win_rate': 53.48837209302326,
'risk_reward_ratio': 1.6350338129618904,
'profit_factor': 1.880288884906174,
'ehlers_ratio': 0.1311829454585705,
'return_on_capital': 0.26978249297565415,
'max_capital_required': 113265.36511172361,
'total_trades': 43,
'pearsonsr': 0.8022110890986095,
'number_of_winning_trades': 23,
'number_of_losing_trades': 20,
'largest_winning_trade': ('2021-01-23 03', 34417.71907928039),
'largest_losing_trade': ('2020-09-21 03', -4627.351985682239)}Do not rely on a single test result. At least do walkforward test with a few iterations.
Run the following to install:
pip install testwise
