Fixed #23651 -- Isolated non-existent fixture tests

Previous versions of the tests were buggy, as initial_data.json
did exist and the test wasn't failing. It was finally failing on
Python 3.4.2.
Thanks Raphaël Hertzog for the report (and Debian bug #765117
contributors).

tests/fixtures/tests.py

@@ -7,6 +7,7 @@
 from django.core import management
 from django.db import connection, IntegrityError
 from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature
+from django.utils.encoding import force_text
 from django.utils import six
 
 from .models import Article, Book, Spy, Tag, Visa
@@ -165,18 +166,6 @@ def test_loading_and_dumping(self):
             '<Book: Music for all ages by Artist formerly known as "Prince" and Django Reinhardt>'
         ])
 
-        # Loading a fixture that doesn't exist emits a warning
-        with warnings.catch_warnings(record=True) as w:
-            warnings.simplefilter("always")
-            management.call_command('loaddata', 'unknown.json', verbosity=0)
-        self.assertEqual(len(w), 1)
-        self.assertTrue(w[0].message, "No fixture named 'unknown' found.")
-
-        # An attempt to load a nonexistent 'initial_data' fixture isn't an error
-        with warnings.catch_warnings(record=True) as w:
-            management.call_command('loaddata', 'initial_data.json', verbosity=0)
-        self.assertEqual(len(w), 0)
-
         # object list is unaffected
         self.assertQuerysetEqual(Article.objects.all(), [
             '<Article: XML identified as leading cause of cancer>',
@@ -396,6 +385,35 @@ def test_output_formats(self):
 <django-objects version="1.0"><object pk="1" model="fixtures.category"><field type="CharField" name="title">News Stories</field><field type="TextField" name="description">Latest news stories</field></object><object pk="2" model="fixtures.article"><field type="CharField" name="headline">Poker has no place on ESPN</field><field type="DateTimeField" name="pub_date">2006-06-16T12:00:00</field></object><object pk="3" model="fixtures.article"><field type="CharField" name="headline">Time to reform copyright</field><field type="DateTimeField" name="pub_date">2006-06-16T13:00:00</field></object><object pk="1" model="fixtures.tag"><field type="CharField" name="name">copyright</field><field to="contenttypes.contenttype" name="tagged_type" rel="ManyToOneRel"><natural>fixtures</natural><natural>article</natural></field><field type="PositiveIntegerField" name="tagged_id">3</field></object><object pk="2" model="fixtures.tag"><field type="CharField" name="name">law</field><field to="contenttypes.contenttype" name="tagged_type" rel="ManyToOneRel"><natural>fixtures</natural><natural>article</natural></field><field type="PositiveIntegerField" name="tagged_id">3</field></object><object pk="1" model="fixtures.person"><field type="CharField" name="name">Django Reinhardt</field></object><object pk="2" model="fixtures.person"><field type="CharField" name="name">Stephane Grappelli</field></object><object pk="3" model="fixtures.person"><field type="CharField" name="name">Prince</field></object><object pk="10" model="fixtures.book"><field type="CharField" name="name">Achieving self-awareness of Python programs</field><field to="fixtures.person" name="authors" rel="ManyToManyRel"></field></object></django-objects>""", format='xml', natural_foreign_keys=True)
 
 
+class NonExistentFixtureTests(TestCase):
+    """
+    Custom class to limit fixture dirs.
+    """
+    available_apps = ['django.contrib.auth', 'django.contrib.contenttypes']
+
+    def test_loaddata_not_existent_fixture_file(self):
+        stdout_output = six.StringIO()
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+            # With verbosity=2, we get both stdout output and a warning
+            management.call_command(
+                'loaddata',
+                'this_fixture_doesnt_exist',
+                verbosity=2,
+                stdout=stdout_output,
+            )
+        self.assertIn("No fixture 'this_fixture_doesnt_exist' in",
+            force_text(stdout_output.getvalue()))
+        self.assertEqual(len(w), 1)
+        self.assertEqual(force_text(w[0].message),
+            "No fixture named 'this_fixture_doesnt_exist' found.")
+
+        # An attempt to load a non-existent 'initial_data' fixture doesn't produce any warning
+        with warnings.catch_warnings(record=True) as w:
+            management.call_command('loaddata', 'initial_data.json', verbosity=0)
+        self.assertEqual(len(w), 0)
+
+
 class FixtureTransactionTests(DumpDataAssertMixin, TransactionTestCase):
 
     available_apps = [

tests/fixtures_regress/tests.py

@@ -17,7 +17,6 @@
 from django.test import (TestCase, TransactionTestCase, skipIfDBFeature,
     skipUnlessDBFeature)
 from django.test import override_settings
-from django.utils.encoding import force_text
 from django.utils._os import upath
 from django.utils import six
 from django.utils.six import PY3, StringIO
@@ -465,18 +464,6 @@ def test_loaddata_no_fixture_specified(self):
                 verbosity=0,
             )
 
-    def test_loaddata_not_existant_fixture_file(self):
-        stdout_output = StringIO()
-        with warnings.catch_warnings(record=True):
-            management.call_command(
-                'loaddata',
-                'this_fixture_doesnt_exist',
-                verbosity=2,
-                stdout=stdout_output,
-            )
-        self.assertTrue("No fixture 'this_fixture_doesnt_exist' in" in
-            force_text(stdout_output.getvalue()))
-
     def test_ticket_20820(self):
         """
         Regression for ticket #20820 -- loaddata on a model that inherits