feat(automatic-exchange-rates): Add Yahoo Finance as a provider via yfinance

app/apps/currencies/tests/test_yfinance_provider.py

@@ -0,0 +1,93 @@
+from decimal import Decimal
+from unittest import TestCase
+
+from apps.currencies.exchange_rates.fetcher import PROVIDER_MAPPING
+from apps.currencies.exchange_rates.providers import YFinanceMarketsProvider
+from apps.currencies.models import ExchangeRateService
+
+
+class _FakeSeries:
+    def __init__(self, values):
+        self._values = values
+
+    def dropna(self):
+        return _FakeSeries([value for value in self._values if value is not None])
+
+    @property
+    def iloc(self):
+        return self
+
+    def __getitem__(self, index):
+        return self._values[index]
+
+
+class _FakeHistory:
+    def __init__(self, close_values):
+        self._close_values = close_values
+        self.empty = not close_values
+
+    def __getitem__(self, field):
+        if field != "Close":
+            raise KeyError(field)
+        return _FakeSeries(self._close_values)
+
+
+class _FakeCurrency:
+    def __init__(self, code, exchange_currency=None):
+        self.code = code
+        self.exchange_currency = exchange_currency
+
+
+class _FakeTicker:
+    def __init__(self, history):
+        self.history_result = history
+        self.history_kwargs = None
+
+    def history(self, **kwargs):
+        self.history_kwargs = kwargs
+        return self.history_result
+
+
+class YFinanceMarketsProviderTests(TestCase):
+    def setUp(self):
+        self.brl = _FakeCurrency("BRL")
+        self.asset = _FakeCurrency("AAPL", exchange_currency=self.brl)
+
+    def test_returns_latest_hourly_close_using_symbol_verbatim(self):
+        ticker = _FakeTicker(_FakeHistory([36.90, None, 37.42]))
+        requested_symbols = []
+
+        def ticker_factory(symbol):
+            requested_symbols.append(symbol)
+            return ticker
+
+        provider = YFinanceMarketsProvider(ticker_factory=ticker_factory)
+
+        rates = provider.get_rates([self.asset], {self.brl})
+
+        self.assertEqual(rates, [(self.brl, self.asset, Decimal("37.42"))])
+        self.assertEqual(requested_symbols, ["AAPL"])
+        self.assertEqual(
+            ticker.history_kwargs,
+            {"period": "5d", "interval": "1h", "auto_adjust": False},
+        )
+
+    def test_passes_brazilian_symbol_verbatim_and_skips_empty_history(self):
+        self.asset.code = "PETR4.SA"
+        ticker = _FakeTicker(_FakeHistory([]))
+        requested_symbols = []
+
+        provider = YFinanceMarketsProvider(
+            ticker_factory=lambda symbol: requested_symbols.append(symbol)
+            or ticker
+        )
+
+        rates = provider.get_rates([self.asset], {self.brl})
+
+        self.assertEqual(rates, [])
+        self.assertEqual(requested_symbols, ["PETR4.SA"])
+
+    def test_is_registered_without_an_api_key(self):
+        self.assertFalse(YFinanceMarketsProvider.requires_api_key())
+        self.assertIs(PROVIDER_MAPPING["yfinance"], YFinanceMarketsProvider)
+        self.assertEqual(ExchangeRateService.ServiceType.YFINANCE, "yfinance")