algorithmic_trading / tests /test_yahoo_data_stream.py
Claude
Fix three correctness bugs in the Yahoo ingest
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import logging
import pandas as pd
import pytest
from unittest.mock import patch
from agentic_ai_system.yahoo_data_stream import YahooDataStream
@pytest.fixture
def yahoo_config():
return {
'data_source': {'type': 'yahoo'},
'yahoo': {'poll_interval_seconds': 1, 'auto_adjust': False},
'trading': {
'symbol': 'AAPL',
'timeframe': '1d',
},
'realtime_data': {'buffer_size': 10},
}
def _sample_yahoo_frame():
idx = pd.date_range('2024-06-03', periods=3, freq='D', tz='America/New_York')
return pd.DataFrame(
{
'Open': [190.0, 191.0, 192.0],
'High': [191.5, 192.5, 193.5],
'Low': [189.0, 190.0, 191.0],
'Close': [191.0, 192.0, 193.0],
'Volume': [1_000_000, 1_100_000, 1_200_000],
},
index=idx,
)
def _split_frame():
"""An unadjusted 10:1 split, as Yahoo returns it with auto_adjust=False.
Modelled on NVDA, 10 June 2024: the raw Close drops from ~1200 to ~120 and
a backtest reads it as a -90% day.
"""
idx = pd.date_range('2024-06-06', periods=4, freq='D', tz='America/New_York')
close = [1200.0, 1208.0, 120.5, 121.0]
return pd.DataFrame(
{
'Open': close,
'High': [c * 1.01 for c in close],
'Low': [c * 0.99 for c in close],
'Close': close,
'Volume': [1_000_000] * 4,
},
index=idx,
)
def _dated_frame(timestamps, close=100.0):
return pd.DataFrame(
{
'timestamp': [pd.Timestamp(t) for t in timestamps],
'open': close,
'high': close,
'low': close,
'close': close,
'volume': 1_000.0,
}
)
class TestYahooDataStream:
def test_initialization_from_symbol(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
assert stream.symbols == ['AAPL']
assert stream.interval == '1d'
def test_normalize_ohlcv(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
df = stream._normalize_ohlcv(_sample_yahoo_frame())
assert list(df.columns) == ['timestamp', 'open', 'high', 'low', 'close', 'volume']
assert len(df) == 3
assert df['close'].iloc[-1] == 193.0
def test_clamp_intraday_lookback(self, yahoo_config):
yahoo_config['trading']['timeframe'] = '1m'
stream = YahooDataStream(yahoo_config)
start, end = stream._clamp_window('2020-01-01', '2026-01-01', '1m')
assert start > '2020-01-01'
assert end >= start
def test_get_historical_data(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
with patch.object(stream, '_download', return_value=_sample_yahoo_frame()):
df = stream.get_historical_data('AAPL', '2024-01-01', '2024-12-31')
assert len(df) == 3
assert 'open' in df.columns
class TestPriceAdjustment:
"""Unadjusted prices turn every split into a phantom crash."""
def test_adjustment_is_on_by_default(self):
stream = YahooDataStream({'trading': {'symbol': 'AAPL', 'timeframe': '1d'}})
assert stream.auto_adjust is True
def test_auto_adjust_is_passed_through_to_yfinance(self):
stream = YahooDataStream({'trading': {'symbol': 'AAPL', 'timeframe': '1d'}})
with patch('yfinance.download', return_value=_sample_yahoo_frame()) as download:
stream._download('AAPL', period='5d', interval='1d')
assert download.call_args.kwargs['auto_adjust'] is True
def test_opting_out_of_adjustment_warns(self, caplog):
with caplog.at_level(logging.WARNING):
YahooDataStream({
'trading': {'symbol': 'AAPL', 'timeframe': '1d'},
'yahoo': {'auto_adjust': False},
})
assert any('not split' in r.message.lower() for r in caplog.records)
def test_split_sized_move_is_flagged(self, yahoo_config, caplog):
stream = YahooDataStream(yahoo_config)
df = stream._normalize_ohlcv(_split_frame())
with caplog.at_level(logging.WARNING):
found = stream._warn_if_unadjusted('NVDA', df)
assert found == 1
assert any('auto_adjust' in r.message for r in caplog.records)
def test_ordinary_moves_are_not_flagged(self, yahoo_config, caplog):
stream = YahooDataStream(yahoo_config)
df = stream._normalize_ohlcv(_sample_yahoo_frame())
with caplog.at_level(logging.WARNING):
assert stream._warn_if_unadjusted('AAPL', df) == 0
def test_intraday_bars_are_not_split_checked(self, yahoo_config):
"""A 40% move in one minute is a halt or a fat finger, not a split."""
yahoo_config['trading']['timeframe'] = '1m'
stream = YahooDataStream(yahoo_config)
df = stream._normalize_ohlcv(_split_frame())
assert stream._warn_if_unadjusted('NVDA', df) == 0
class TestIncompleteBars:
"""The bar Yahoo is still building must not be reported as final."""
def test_forming_bar_is_dropped(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
now = pd.Timestamp.now(tz='UTC').tz_convert(None).normalize()
df = _dated_frame([now - pd.Timedelta(days=2), now - pd.Timedelta(days=1), now])
kept = stream._drop_incomplete(df)
assert len(kept) == 2
assert kept['timestamp'].max() < now
def test_finished_bars_all_survive(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
now = pd.Timestamp.now(tz='UTC').tz_convert(None).normalize()
df = _dated_frame([now - pd.Timedelta(days=5), now - pd.Timedelta(days=4)])
assert len(stream._drop_incomplete(df)) == 2
def test_opting_in_keeps_the_forming_bar(self, yahoo_config):
yahoo_config['yahoo']['emit_incomplete_bars'] = True
stream = YahooDataStream(yahoo_config)
now = pd.Timestamp.now(tz='UTC').tz_convert(None).normalize()
df = _dated_frame([now - pd.Timedelta(days=1), now])
assert len(stream._drop_incomplete(df)) == 2
def test_partial_bar_is_never_emitted_then_stranded(self, yahoo_config):
"""The bug this guards: emitting the forming bar advanced the watermark,
so the finished version of that same bar never reached a callback."""
stream = YahooDataStream(yahoo_config)
received = []
stream.add_data_callback(lambda kind, bar: received.append(bar))
now = pd.Timestamp.now(tz='UTC').tz_convert(None).normalize()
yesterday, today = now - pd.Timedelta(days=1), now
stream._ingest_new_bars('AAPL', _dated_frame([yesterday, today], close=100.0))
assert len(received) == 1 # only yesterday's completed bar
# Next day: what was the forming bar is now final and must arrive.
with patch.object(stream, '_drop_incomplete', side_effect=lambda d: d):
stream._ingest_new_bars('AAPL', _dated_frame([yesterday, today], close=105.0))
assert len(received) == 2
assert received[-1]['close'] == 105.0
class TestPollBackoff:
"""Yahoo rate-limits hard, and a fixed interval keeps you throttled."""
def test_success_polls_at_the_configured_interval(self, yahoo_config):
yahoo_config['yahoo']['poll_interval_seconds'] = 60
stream = YahooDataStream(yahoo_config)
stream._consecutive_failures = 0
assert 48 <= stream._next_delay() <= 72 # 60s +/- jitter
def test_delay_grows_with_consecutive_failures(self, yahoo_config):
yahoo_config['yahoo']['poll_interval_seconds'] = 60
stream = YahooDataStream(yahoo_config)
delays = []
for failures in (1, 2, 3):
stream._consecutive_failures = failures
delays.append(stream._next_delay())
assert delays[0] < delays[1] < delays[2]
def test_backoff_is_capped(self, yahoo_config):
yahoo_config['yahoo']['poll_interval_seconds'] = 60
yahoo_config['yahoo']['max_backoff_seconds'] = 300
stream = YahooDataStream(yahoo_config)
stream._consecutive_failures = 20
assert stream._next_delay() <= 300 * 1.2
def test_jitter_desynchronises_retries(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
stream._consecutive_failures = 3
assert len({stream._next_delay() for _ in range(20)}) > 1
def test_poll_reports_failure_when_every_symbol_fails(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
with patch.object(stream, '_download', side_effect=RuntimeError('429 Too Many Requests')):
assert stream._poll_once() is False
def test_poll_reports_success_when_a_symbol_returns_bars(self, yahoo_config):
stream = YahooDataStream(yahoo_config)
with patch.object(stream, '_download', return_value=_sample_yahoo_frame()):
assert stream._poll_once() is True
def test_empty_response_counts_as_failure(self, yahoo_config):
"""A rate-limited yfinance returns an empty frame rather than raising."""
stream = YahooDataStream(yahoo_config)
with patch.object(stream, '_download', return_value=pd.DataFrame()):
assert stream._poll_once() is False