Merge pull request #24 from MELScience/ff_value_to_string

Added `value_to_string` method

localized_fields/fields/file_field.py

@@ -1,3 +1,4 @@
+import json
 import datetime
 import posixpath
 
@@ -149,3 +150,11 @@ class LocalizedFileField(LocalizedField):
             defaults['required'] = False
         defaults.update(kwargs)
         return super().formfield(**defaults)
+
+    def value_to_string(self, obj):
+        value = self.value_from_object(obj)
+        if isinstance(value, LocalizedFileValue):
+            return json.dumps({k: v.name for k, v
+                               in value.__dict__.items()})
+        else:
+            return super().value_to_string(obj)

tests/test_file_field.py

@@ -2,6 +2,7 @@ import os
 import shutil
 import tempfile as sys_tempfile
 import pickle
+import json
 
 from django import forms
 from django.test import TestCase, override_settings
@@ -118,6 +119,20 @@ class LocalizedFileFieldTestCase(TestCase):
         filename = field.generate_filename(instance, 'test', 'en')
         assert filename == 'en_test'
 
+    @classmethod
+    @override_settings(LANGUAGES=(('en', 'English'),))
+    def test_value_to_string(cls):
+        """Tests whether the :see:LocalizedFileField
+        class's :see:value_to_string function works properly."""
+
+        temp_file = File(tempfile.NamedTemporaryFile())
+        instance = cls.FileFieldModel()
+        field = cls.FileFieldModel._meta.get_field('file')
+        field.upload_to = ''
+        instance.file.en.save('testfilename', temp_file)
+        expected_value_to_string = json.dumps({'en': 'testfilename'})
+        assert field.value_to_string(instance) == expected_value_to_string
+
     @staticmethod
     def test_get_prep_value():
         """Tests whether the :see:get_prep_value function returns correctly