[pull] main from django:main

django/db/models/query.py

@@ -1416,11 +1416,14 @@ def values(self, *fields, **expressions):
     def values_list(self, *fields, flat=False, named=False):
         if flat and named:
             raise TypeError("'flat' and 'named' can't be used together.")
-        if flat and len(fields) > 1:
-            raise TypeError(
-                "'flat' is not valid when values_list is called with more than one "
-                "field."
-            )
+        if flat:
+            if len(fields) > 1:
+                raise TypeError(
+                    "'flat' is not valid when values_list is called with more than one "
+                    "field."
+                )
+            elif not fields:
+                fields = [self.model._meta.concrete_fields[0].attname]
 
         field_names = {f: False for f in fields if not hasattr(f, "resolve_expression")}
         _fields = []

django/test/runner.py

@@ -439,7 +439,7 @@ def _init_worker(
     used_aliases=None,
 ):
     """
-    Switch to databases dedicated to this worker.
+    Switch to databases dedicated to this worker and run system checks.
 
     This helper lives at module-level because of the multiprocessing module's
     requirements.
@@ -463,6 +463,9 @@ def _init_worker(
             process_setup(*process_setup_args)
         django.setup()
         setup_test_environment(debug=debug_mode)
+        call_command(
+            "check", stdout=io.StringIO(), stderr=io.StringIO(), databases=used_aliases
+        )
 
     db_aliases = used_aliases if used_aliases is not None else connections
     for alias in db_aliases:

tests/lookup/tests.py

@@ -327,6 +327,25 @@ def test_in_bulk_not_model_iterable(self):
     def test_values(self):
         # values() returns a list of dictionaries instead of object instances,
         # and you can specify which fields you want to retrieve.
+        self.assertSequenceEqual(
+            Article.objects.filter(id__in=(self.a5.id, self.a6.id)).values(),
+            [
+                {
+                    "id": self.a5.id,
+                    "headline": "Article 5",
+                    "pub_date": datetime(2005, 8, 1, 9, 0),
+                    "author_id": self.au2.id,
+                    "slug": "a5",
+                },
+                {
+                    "id": self.a6.id,
+                    "headline": "Article 6",
+                    "pub_date": datetime(2005, 8, 1, 8, 0),
+                    "author_id": self.au2.id,
+                    "slug": "a6",
+                },
+            ],
+        )
         self.assertSequenceEqual(
             Article.objects.values("headline"),
             [
@@ -522,6 +541,37 @@ def test_values_list(self):
         # returned as a list of tuples, rather than a list of dictionaries.
         # Within each tuple, the order of the elements is the same as the order
         # of fields in the values_list() call.
+        self.assertSequenceEqual(
+            Article.objects.filter(id__in=(self.a5.id, self.a6.id)).values_list(),
+            [
+                (
+                    self.a5.id,
+                    "Article 5",
+                    datetime(2005, 8, 1, 9, 0),
+                    self.au2.id,
+                    "a5",
+                ),
+                (
+                    self.a6.id,
+                    "Article 6",
+                    datetime(2005, 8, 1, 8, 0),
+                    self.au2.id,
+                    "a6",
+                ),
+            ],
+        )
+        self.assertSequenceEqual(
+            Article.objects.values_list(flat=True),
+            [
+                self.a5.id,
+                self.a6.id,
+                self.a4.id,
+                self.a2.id,
+                self.a3.id,
+                self.a7.id,
+                self.a1.id,
+            ],
+        )
         self.assertSequenceEqual(
             Article.objects.values_list("headline"),
             [

tests/test_runner/models.py

@@ -6,6 +6,13 @@ class Person(models.Model):
     last_name = models.CharField(max_length=20)
     friends = models.ManyToManyField("self")
 
+    system_check_run_count = 0
+
+    @classmethod
+    def check(cls, *args, **kwargs):
+        cls.system_check_run_count += 1
+        return super().check(**kwargs)
+
 
 # A set of models that use a non-abstract inherited 'through' model.
 class ThroughBase(models.Model):

tests/test_runner/test_parallel.py

@@ -8,6 +8,8 @@
 from django.test import SimpleTestCase
 from django.test.runner import ParallelTestSuite, RemoteTestResult
 
+from . import models
+
 try:
     import tblib.pickling_support
 except ImportError:
@@ -48,6 +50,9 @@ def test_subtest(self):
             with self.subTest(index=i):
                 self.assertEqual(i, i)
 
+    def test_system_checks(self):
+        self.assertEqual(models.Person.system_check_run_count, 1)
+
 
 class SampleFailingSubtest(SimpleTestCase):
     # This method name doesn't begin with "test" to prevent test discovery