Fix tests that use non-default collation

tests/db_functions/comparison/test_collate.py

@@ -1,6 +1,6 @@
 from django.db import connection
-from django.db.models import F, Value
-from django.db.models.functions import Collate
+from django.db.models import F, Value, TextField
+from django.db.models.functions import Collate, Cast
 from django.test import TestCase
 
 from ..models import Author
@@ -13,10 +13,12 @@ def setUpTestData(cls):
         cls.author2 = Author.objects.create(alias="A", name="Jones 2")
 
     def test_collate_filter_ci(self):
-        collation = connection.features.test_collations.get("ci")
-        if not collation:
+        collation_ci = connection.features.test_collations.get("ci")
+        if not collation_ci:
             self.skipTest("This backend does not support case-insensitive collations.")
-        qs = Author.objects.filter(alias=Collate(Value("a"), collation))
+        qs = Author.objects.annotate(
+            alias_ci=Cast("alias", TextField(db_collation=collation_ci))
+        ).filter(alias_ci=Collate(Value("a"), collation_ci))
         self.assertEqual(qs.count(), 2)
 
     def test_collate_order_by_cs(self):

tests/inspectdb/tests.py

@@ -76,26 +76,49 @@ def test_field_types(self):
         Test introspection of various Django field types. In SingleStore,
         db_collation is always included to the introspection result of a char field
         """
+        with connection.cursor() as cur:
+            cur.execute("SELECT @@collation_database")
+            results = cur.fetchall()
+            default_collation = results[0][0]
+
         assertFieldType = self.make_field_type_asserter()
         introspected_field_types = connection.features.introspected_field_types
         char_field_type = introspected_field_types["CharField"]
-        # Inspecting Oracle DB doesn't produce correct results (#19884):
-        # - it reports fields as blank=True when they aren't.
         if (
             not connection.features.interprets_empty_strings_as_nulls
             and char_field_type == "CharField"
         ):
-            assertFieldType("char_field", "models.CharField(max_length=10, db_collation='utf8mb4_general_ci')")
+            assertFieldType(
+                "char_field",
+                f"models.CharField(max_length=10, db_collation='{default_collation}')",
+            )
             assertFieldType(
                 "null_char_field",
-                "models.CharField(max_length=10, db_collation='utf8mb4_general_ci', blank=True, null=True)",
-            )
-            assertFieldType("email_field", "models.CharField(max_length=254, db_collation='utf8mb4_general_ci')")
-            assertFieldType("file_field", "models.CharField(max_length=100, db_collation='utf8mb4_general_ci')")
-            assertFieldType("file_path_field", "models.CharField(max_length=100, db_collation='utf8mb4_general_ci')")
-            assertFieldType("slug_field", "models.CharField(max_length=50, db_collation='utf8mb4_general_ci')")
-            assertFieldType("text_field", "models.TextField(db_collation='utf8mb4_general_ci')")
-            assertFieldType("url_field", "models.CharField(max_length=200, db_collation='utf8mb4_general_ci')")
+                f"models.CharField(max_length=10, db_collation='{default_collation}', blank=True, null=True)",
+            )
+            assertFieldType(
+                "email_field",
+                f"models.CharField(max_length=254, db_collation='{default_collation}')",
+            )
+            assertFieldType(
+                "file_field",
+                f"models.CharField(max_length=100, db_collation='{default_collation}')",
+            )
+            assertFieldType(
+                "file_path_field",
+                f"models.CharField(max_length=100, db_collation='{default_collation}')",
+            )
+            assertFieldType(
+                "slug_field",
+                f"models.CharField(max_length=50, db_collation='{default_collation}')",
+            )
+            assertFieldType(
+                "text_field", f"models.TextField(db_collation='{default_collation}')"
+            )
+            assertFieldType(
+                "url_field",
+                f"models.CharField(max_length=200, db_collation='{default_collation}')",
+            )
         if char_field_type == "TextField":
             assertFieldType("char_field", "models.TextField()")
             assertFieldType(
@@ -112,14 +135,20 @@ def test_field_types(self):
         if introspected_field_types["GenericIPAddressField"] == "GenericIPAddressField":
             assertFieldType("gen_ip_address_field", "models.GenericIPAddressField()")
         elif not connection.features.interprets_empty_strings_as_nulls:
-            assertFieldType("gen_ip_address_field", "models.CharField(max_length=39, db_collation='utf8mb4_general_ci')")
+            assertFieldType(
+                "gen_ip_address_field",
+                f"models.CharField(max_length=39, db_collation='{default_collation}')",
+            )
         assertFieldType(
             "time_field", "models.%s()" % introspected_field_types["TimeField"]
         )
         if connection.features.has_native_uuid_field:
             assertFieldType("uuid_field", "models.UUIDField()")
         elif not connection.features.interprets_empty_strings_as_nulls:
-            assertFieldType("uuid_field", "models.CharField(max_length=32, db_collation='utf8mb4_general_ci')")
+            assertFieldType(
+                "uuid_field",
+                f"models.CharField(max_length=32, db_collation='{default_collation}')",
+            )
 
     @skipUnlessDBFeature("can_introspect_json_field", "supports_json_field")
     def test_json_field(self):