mark NthValue as unsupported, and skip related tests

Author: Tim Nyborg

mssql/functions.py

@@ -4,8 +4,9 @@
 import json
 
 from django import VERSION
+from django.db import NotSupportedError
 from django.db.models import BooleanField, Value
-from django.db.models.functions import Cast
+from django.db.models.functions import Cast, NthValue
 from django.db.models.functions.math import ATan2, Log, Ln, Mod, Round
 from django.db.models.expressions import Case, Exists, OrderBy, When, Window
 from django.db.models.lookups import Lookup, In
@@ -51,6 +52,10 @@ def sqlserver_mod(self, compiler, connection):
     )
 
 
+def sqlserver_nth_value(self, compiler, connection, **extra_content):
+    raise NotSupportedError('This backend does not support the NthValue function')
+
+
 def sqlserver_round(self, compiler, connection, **extra_context):
     return self.as_sql(compiler, connection, template='%(function)s(%(expressions)s, 0)', **extra_context)
 
@@ -186,6 +191,7 @@ def json_HasKeyLookup(self, compiler, connection):
 Ln.as_microsoft = sqlserver_ln
 Log.as_microsoft = sqlserver_log
 Mod.as_microsoft = sqlserver_mod
+NthValue.as_microsoft = sqlserver_nth_value
 Round.as_microsoft = sqlserver_round
 Window.as_microsoft = sqlserver_window
 

testapp/settings.py

@@ -54,6 +54,8 @@
                   'expressions.tests.FTimeDeltaTests.test_duration_with_datetime_microseconds',
                   'expressions.tests.IterableLookupInnerExpressionsTests.test_expressions_in_lookups_join_choice',
                   'expressions_case.tests.CaseExpressionTests.test_annotate_with_in_clause',
+                  'expressions_window.tests.WindowFunctionTests.test_nth_returns_null',
+                  'expressions_window.tests.WindowFunctionTests.test_nthvalue',
                   'ordering.tests.OrderingTests.test_orders_nulls_first_on_filtered_subquery',
                   'queries.test_bulk_update.BulkUpdateNoteTests.test_set_field_to_null',
                   'get_or_create.tests.UpdateOrCreateTransactionTests.test_creation_in_transaction',