Throw exception on invalid route53 interval option value

octodns/provider/route53.py

@@ -553,8 +553,12 @@ class Route53Provider(BaseProvider):
     def _healthcheck_request_interval(self, record):
         interval = record._octodns.get('route53', {}) \
             .get('healthcheck', {}) \
-            .get('request_interval')
-        return interval if (interval in [10, 30]) else 10
+            .get('request_interval', 10)
+        if (interval in [10, 30]):
+            return interval
+        else:
+            raise Exception('route53.healthcheck.request_interval '
+                            'parameter must be either 10 or 30.')
 
     def _health_check_equivilent(self, host, path, protocol, port,
                                  measure_latency, request_interval,

tests/test_octodns_provider_route53.py

@@ -930,6 +930,23 @@ class TestRoute53Provider(TestCase):
         self.assertFalse(latency)
         self.assertEquals(30, interval)
 
+        record_invalid = Record.new(self.expected, 'a', {
+            'ttl': 61,
+            'type': 'A',
+            'value': '1.2.3.4',
+            'octodns': {
+                'healthcheck': {
+                },
+                'route53': {
+                    'healthcheck': {
+                        'request_interval': 20,
+                    }
+                }
+            }
+        })
+        with self.assertRaises(Exception):
+            interval = provider._healthcheck_request_interval(record_invalid)
+
     def test_create_health_checks_provider_options(self):
         provider, stubber = self._get_stubbed_provider()