Fixed #26891 -- Fixed lookup registration for ForeignObject.

2 files changed, 27 insertions, 1 deletions

diff --git a/tests/custom_lookups/models.py b/tests/custom_lookups/models.py
index 82a835e160..97979dd953 100644
--- a/tests/custom_lookups/models.py
+++ b/tests/custom_lookups/models.py
@@ -13,6 +13,10 @@ class Author(models.Model):
         return self.name
 
 
+class Article(models.Model):
+    author = models.ForeignKey(Author, on_delete=models.CASCADE)
+
+
 @python_2_unicode_compatible
 class MySQLUnixTimestamp(models.Model):
     timestamp = models.PositiveIntegerField()
diff --git a/tests/custom_lookups/tests.py b/tests/custom_lookups/tests.py
index c538d23b76..da9274904c 100644
--- a/tests/custom_lookups/tests.py
+++ b/tests/custom_lookups/tests.py
@@ -10,7 +10,7 @@ from django.db import connection, models
 from django.test import TestCase, override_settings
 from django.utils import timezone
 
-from .models import Author, MySQLUnixTimestamp
+from .models import Article, Author, MySQLUnixTimestamp
 
 
 @contextlib.contextmanager
@@ -319,6 +319,28 @@ class LookupTests(TestCase):
                 baseqs.filter(age__div3__range=(1, 2)),
                 [a1, a2, a4], lambda x: x)
 
+    def test_foreignobject_lookup_registration(self):
+        field = Article._meta.get_field('author')
+
+        with register_lookup(models.ForeignObject, Exactly):
+            self.assertIs(field.get_lookup('exactly'), Exactly)
+
+        # ForeignObject should ignore regular Field lookups
+        with register_lookup(models.Field, Exactly):
+            self.assertIsNone(field.get_lookup('exactly'))
+
+    def test_lookups_caching(self):
+        field = Article._meta.get_field('author')
+
+        # clear and re-cache
+        field.get_lookups.cache_clear()
+        self.assertNotIn('exactly', field.get_lookups())
+
+        # registration should bust the cache
+        with register_lookup(models.ForeignObject, Exactly):
+            # getting the lookups again should re-cache
+            self.assertIn('exactly', field.get_lookups())
+
 
 class BilateralTransformTests(TestCase):