Validate type of recipients

sparkpost/transmissions.py

@@ -4,6 +4,7 @@
 from email.utils import parseaddr
 
 from .base import Resource
+from .exceptions import SparkPostException
 
 
 try:
@@ -137,6 +138,10 @@ def _parse_address(self, address):
         return parsed_address
 
     def _extract_recipients(self, recipients):
+
+        if not (isinstance(recipients, list) or isinstance(recipients, dict)):
+            raise SparkPostException('recipients must be a list or dict')
+
         formatted_recipients = []
         for recip in recipients:
             if isinstance(recip, string_types):

test/test_transmissions.py

@@ -9,7 +9,7 @@
 
 from sparkpost import SparkPost
 from sparkpost import Transmissions
-from sparkpost.exceptions import SparkPostAPIException
+from sparkpost.exceptions import SparkPostAPIException, SparkPostException
 
 
 def test_translate_keys_with_list():
@@ -28,6 +28,19 @@ def test_translate_keys_with_recips():
                                      {'key': 'value'},
                                      {'address': {'email': 'foobar'}}]
 
+    results = t._translate_keys(
+        recipients=[{'address': {'name': 'foo', 'email': 'bar'}}]
+    )
+    assert results['recipients'] == [
+            {'address': {'name': 'foo', 'email': 'bar'}}
+    ]
+
+
+def test_exceptions_for_recipients():
+    t = Transmissions('uri', 'key')
+    with pytest.raises(SparkPostException):
+        t._translate_keys(recipients='test')
+
 
 def test_translate_keys_with_unicode_recips():
     t = Transmissions('uri', 'key')