Add SaveDollarPrefixTests test case

Author: WaVEV

tests/basic_/__init__.py

@@ -0,0 +1,8 @@
+from django.db import models
+
+
+class Author(models.Model):
+    name = models.CharField(max_length=10)
+
+    def __str__(self):
+        return self.name

tests/basic_/models.py

@@ -0,0 +1,13 @@
+from django.test import TestCase
+
+from django_mongodb_backend.test import MongoTestCaseMixin
+
+from .models import Author
+
+
+class SaveDollarPrefixTests(MongoTestCaseMixin, TestCase):
+    def test_insert_dollar_prefix(self):
+        """$-prefixed values are correctly saved on insert."""
+        obj = Author.objects.create(name="$foobar")
+        obj.refresh_from_db()
+        self.assertEqual(obj.name, "$foobar")