Fix ticker interval

[jblestang]

Using the ticker interval configured by the user and fixing the average time duration estimation in the backtest script

[glonlas]

I applied it and it works perfectly, the code is straightforward. However, the unittest is missing.

@jblestang you can add this following unitest to test that backtesting is loading 1 min ticker instead of 5.

1. in tests/testdata mock a 1 ticker interval file for the purpose of this PR. It simulates a 1min file that does not have a 5min version)
2. in test/test_optimize_backtesting.py add the following tests.
3. you can fix the typo on "result" line 15 and 16 (resutls to results)

Add a mock file

In test/testdataduplicate a 1min ticker file and rename it, BTC_UNITEST-1.json. DO NOT do the same with the 5 min ticker.

Import pytest

In test/test_optimize_backtesting.py add on Line 7

import pytest

Add the unitest

In test/test_optimize_backtesting.py add on Line 19

def test_1min_ticker_interval(default_conf, mocker):
    mocker.patch.dict('freqtrade.main._CONF', default_conf)
    exchange._API = Bittrex({'key': '', 'secret': ''})

    # Run a backtesting for an exiting 5min ticker_interval
    data = optimize.load_data(ticker_interval=1, pairs=['BTC_UNITEST'])
    results = backtest(default_conf, optimize.preprocess(data), 1, True)
    assert len(results) > 0

    # Run a backtesting for 5min ticker_interval
    with pytest.raises(FileNotFoundError):
        data = optimize.load_data(ticker_interval=5, pairs=['BTC_UNITEST'])
        results = backtest(default_conf, optimize.preprocess(data), 1, True)

Re run test

pytest freqtrade/tests/test_optimize_backtesting.py should pass

[vertti]

@jblestang thanks for the fix!
@glonlas holy shit you are on fire with your PR reviews, thanks for all the effort!

[jblestang]

The requested unit test has been added. Thanks @glonlas for showing how to do it!