Handle unicode error in json serialize properly.

tests/unit/test_serialize.py

@@ -1,21 +1,34 @@
+import mock
 import pytest
+
 from vcr.serialize import deserialize
 from vcr.serializers import yamlserializer, jsonserializer
 
+
 def test_deserialize_old_yaml_cassette():
     with open('tests/fixtures/migration/old_cassette.yaml', 'r') as f:
         with pytest.raises(ValueError):
             deserialize(f.read(), yamlserializer)
 
+
 def test_deserialize_old_json_cassette():
     with open('tests/fixtures/migration/old_cassette.json', 'r') as f:
         with pytest.raises(ValueError):
             deserialize(f.read(), jsonserializer)
 
+
 def test_deserialize_new_yaml_cassette():
     with open('tests/fixtures/migration/new_cassette.yaml', 'r') as f:
         deserialize(f.read(), yamlserializer)
 
+
 def test_deserialize_new_json_cassette():
     with open('tests/fixtures/migration/new_cassette.json', 'r') as f:
         deserialize(f.read(), jsonserializer)
+
+
+@mock.patch.object(jsonserializer.json, 'dumps',
+                   side_effect=UnicodeDecodeError('utf-8', b'unicode error in serialization',
+                                                  0, 10, 'blew up'))
+def test_serialize_constructs_UnicodeDecodeError(mock_dumps):
+    jsonserializer.serialize({})