Add singling links tests

jet/tests/admin.py

@@ -0,0 +1,8 @@
+from django.contrib import admin
+from jet.tests.models import TestModel
+
+
+class TestModelAdmin(admin.ModelAdmin):
+    list_display = ('field1', 'field2')
+
+admin.site.register(TestModel, TestModelAdmin)

jet/tests/test_tags.py

@@ -1,6 +1,7 @@
 from django import forms
+from django.core.urlresolvers import reverse
 from django.test import TestCase
-from jet.templatetags.jet_tags import select2_lookups
+from jet.templatetags.jet_tags import select2_lookups, jet_sibling_object_url
 from jet.tests.models import TestModel, SearchableTestModel
 
 
@@ -55,4 +56,35 @@ class TagsTestCase(TestCase):
 
         self.assertEqual(len(choices), len(self.models) + 1)
 
+    def test_jet_sibling_object_next_url(self):
+        instance = self.models[0]
+        ordering_field = 1  # field1 in list_display
+        preserved_filters = '_changelist_filters=o%%3D%d' % ordering_field
 
+        context = {
+            'original': instance,
+            'preserved_filters': preserved_filters
+        }
+
+        actual_url = jet_sibling_object_url(context, next=True)
+        expected_url = reverse('admin:%s_%s_change' % (
+            TestModel._meta.app_label,
+            TestModel._meta.model_name
+        ), args=(self.models[1].pk,)) + '?' + preserved_filters
+
+        self.assertEqual(actual_url, expected_url)
+
+    def test_jet_sibling_object_previous_url(self):
+        instance = self.models[0]
+        ordering_field = 1  # field1 in list_display
+        preserved_filters = '_changelist_filters=o%%3D%d' % ordering_field
+
+        context = {
+            'original': instance,
+            'preserved_filters': preserved_filters
+        }
+
+        actual_url = jet_sibling_object_url(context, next=False)
+        expected_url = None
+
+        self.assertEqual(actual_url, expected_url)