Raise exception when rate date is not the requested

The API return the latest rate when requesting a rate for a date for
which it is not yet available like in the future.

Author: cedk

forex_python/converter.py

@@ -32,15 +32,21 @@ def _get_date_string(self, date_obj):
         date_str = date_obj.strftime('%Y-%m-%d')
         return date_str
 
-    def _decode_rates(self, response, use_decimal=False):
+    def _decode_rates(self, response, use_decimal=False, date_str=None):
         if self._force_decimal or use_decimal:
-            decoded_data = json.loads(response.text, use_decimal=True).get('rates', {})
+            decoded_data = json.loads(response.text, use_decimal=True)
         else:
-            decoded_data = response.json().get('rates', {})
-        return decoded_data
+            decoded_data = response.json()
+        if (date_str and date_str != 'latest'
+                and date_str != decoded_data.get('date')):
+            raise RatesNotAvailableError("Currency Rates Source Not Ready")
+        return decoded_data.get('rates', {})
 
-    def _get_decoded_rate(self, response, dest_cur, use_decimal=False):
-        return self._decode_rates(response, use_decimal=use_decimal).get(dest_cur, None)
+    def _get_decoded_rate(
+            self, response, dest_cur, use_decimal=False, date_str=None):
+        return self._decode_rates(
+            response, use_decimal=use_decimal, date_str=date_str).get(
+                dest_cur, None)
 
 
 class CurrencyRates(Common):
@@ -51,7 +57,7 @@ def get_rates(self, base_cur, date_obj=None):
         source_url = self._source_url() + date_str
         response = requests.get(source_url, params=payload)
         if response.status_code == 200:
-            rates = self._decode_rates(response)
+            rates = self._decode_rates(response, date_str=date_str)
             return rates
         raise RatesNotAvailableError("Currency Rates Source Not Ready")
 
@@ -65,7 +71,7 @@ def get_rate(self, base_cur, dest_cur, date_obj=None):
         source_url = self._source_url() + date_str
         response = requests.get(source_url, params=payload)
         if response.status_code == 200:
-            rate = self._get_decoded_rate(response, dest_cur)
+            rate = self._get_decoded_rate(response, dest_cur, date_str=date_str)
             if not rate:
                 raise RatesNotAvailableError("Currency Rate {0} => {1} not available for Date {2}".format(
                     base_cur, dest_cur, date_str))
@@ -88,7 +94,8 @@ def convert(self, base_cur, dest_cur, amount, date_obj=None):
         source_url = self._source_url() + date_str
         response = requests.get(source_url, params=payload)
         if response.status_code == 200:
-            rate = self._get_decoded_rate(response, dest_cur, use_decimal=use_decimal)
+            rate = self._get_decoded_rate(
+                response, dest_cur, use_decimal=use_decimal, date_str=date_str)
             if not rate:
                 raise RatesNotAvailableError("Currency {0} => {1} rate not available for Date {2}.".format(
                     source_url, dest_cur, date_str))

tests/test.py

@@ -39,6 +39,10 @@ def test_get_rates_with_date(self):
     def test_get_rates_invalid_code(self):
         self.assertRaises(RatesNotAvailableError, get_rates, 'XYZ')
 
+    def test_get_rates_in_future(self):
+        future = datetime.date.today() + datetime.timedelta(days=1)
+        self.assertRaises(RatesNotAvailableError, get_rates, 'USD', future)
+
 
 class TestGetRate(TestCase):
     """
@@ -67,6 +71,11 @@ def test_get_rate_with_invalid_codes(self):
         # raise exception for invalid currency codes
         self.assertRaises(RatesNotAvailableError, get_rate, 'ABCD', 'XYZ')
 
+    def test_get_rates_in_future(self):
+        future = datetime.date.today() + datetime.timedelta(days=1)
+        self.assertRaises(
+            RatesNotAvailableError, get_rate, 'EUR', 'USD', future)
+
 
 class TestAmountConvert(TestCase):
     """