Tolerate broken CSV files (#62)

ibkr_report/exchangerates.py

@@ -68,10 +68,9 @@ def add_to_exchange_rates(self, rates_file: Iterable[bytes]) -> None:
             if currencies and re.match(r"^\d\d\d\d-\d\d-\d\d$", items[0]):
                 # And the following rows like "2015-01-20,1.1579,137.37,..."
                 date_rates = {}
-                for key, val in enumerate(items):
-                    if key == 0 or not currencies[key] or not is_number(val):
-                        continue
-                    date_rates[currencies[key]] = val
+                for cur, val in zip(currencies, items):
+                    if is_number(val):
+                        date_rates[cur] = val
                 if date_rates:
                     rates[items[0]] = date_rates
         log.debug("Adding currency data from %d rows.", len(rates))

test-data/eurofxref-broken.csv

@@ -0,0 +1,3 @@
+Date,USD
+2021-10-27
+2021-10-26,1.1618,132.47

test.py

@@ -274,6 +274,14 @@ def test_far_in_the_future(self):
         with self.assertRaises(ValueError):
             self.rates.get_rate("USD", "CAD", "2500-01-01")
 
+    def test_broken_input(self):
+        with open("test-data/eurofxref-broken.csv", "rb") as file:
+            self.rates.add_to_exchange_rates(file)
+        eur_usd = self.rates.get_rate("EUR", "USD", "2021-10-26")
+        self.assertEqual(eur_usd, Decimal("1.1618"))
+        eur_usd = self.rates.get_rate("EUR", "USD", "2021-10-25")
+        self.assertEqual(eur_usd, Decimal("1.1603"))
+
 
 if __name__ == "__main__":
     unittest.main()