def test_get_prep_value_correct_values_json(self):
f = JSignatureField()
val = [{"x": [1, 2], "y": [3, 4]}]
val_str = '[{"x":[1,2], "y":[3,4]}]'
val_prep = f.get_prep_value(val_str)
self.assertIsInstance(val_prep, six.string_types)
self.assertEquals(val, json.loads(val_prep))
def test_get_prep_value_empty(self):
f = JSignatureField()
for val in ['', [], '[]']:
self.assertIsNone(f.get_prep_value(val))