test: each app keeps its tests in a tests package

131 test modules sat next to the code they test; instances alone had
51 of them beside views.py and utils.py. They move into a
tests/ package per app, and the JavaScript checks into
webvirtcloud/tests/js. Each non-empty tests.py becomes tests/test_views.py;
the empty generated stubs are removed.

Imports of the app's own modules become absolute, paths built from
__file__ go one level up, the live helper is instances.tests.livetest,
and coverage omits */tests/*. The suite discovers the same 960 tests as
before.

admin/test_user_create.py

@@ -1,65 +0,0 @@
-"""Creating a user in the admin pages: the password reaches the database only
-hashed, and the configured password validators apply as on the change forms."""
-
-from django.contrib.auth.models import Group, Permission, User
-from django.db import connection
-from django.test import TestCase, override_settings
-from django.urls import reverse
-
-RAW = "Raw-Passw0rd-in-the-form"
-LIMITS = {"max_instances": 1, "max_cpus": 1, "max_memory": 1024, "max_disk_size": 4}
-
-
-class UserCreateTests(TestCase):
-    def setUp(self):
-        self.client.force_login(User.objects.create_superuser("uc-admin", "uc@example.com", "pw"))
-        self.change_password = Permission.objects.get(content_type__app_label="accounts", codename="change_password")
-
-    def create(self, **data):
-        return self.client.post(reverse("admin:user_create"), {"username": "newbie", "password": RAW, **LIMITS, **data})
-
-    def test_the_raw_password_is_never_written(self):
-        written = []
-
-        def record(execute, sql, params, many, context):
-            if RAW in repr(params):
-                written.append(sql)
-            return execute(sql, params, many, context)
-
-        with connection.execute_wrapper(record):
-            response = self.create()
-        self.assertRedirects(response, reverse("admin:user_list"))
-        self.assertEqual(written, [])
-        self.assertTrue(User.objects.get(username="newbie").check_password(RAW))
-
-    def test_groups_and_permissions_are_saved(self):
-        group = Group.objects.create(name="uc-group")
-        self.create(groups=[group.pk], user_permissions=[self.change_password.pk])
-        user = User.objects.get(username="newbie")
-        self.assertEqual(list(user.groups.all()), [group])
-        self.assertEqual(list(user.user_permissions.all()), [self.change_password])
-
-    def test_an_unticked_permission_stays_off(self):
-        self.create()
-        self.assertFalse(User.objects.get(username="newbie").user_permissions.exists())
-
-    @override_settings(
-        AUTH_PASSWORD_VALIDATORS=[
-            {"NAME": "django.contrib.auth.password_validation.MinimumLengthValidator", "OPTIONS": {"min_length": 30}}
-        ]
-    )
-    def test_configured_password_validators_apply(self):
-        response = self.create()
-        self.assertEqual(response.status_code, 200)
-        self.assertContains(response, "at least 30 characters")
-        self.assertFalse(User.objects.filter(username="newbie").exists())
-
-    @override_settings(
-        AUTH_PASSWORD_VALIDATORS=[{"NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator"}]
-    )
-    def test_the_password_is_checked_against_the_new_username(self):
-        response = self.client.post(
-            reverse("admin:user_create"), {"username": "rumpelstiltskin", "password": "rumpelstiltskin1", **LIMITS}
-        )
-        self.assertEqual(response.status_code, 200)
-        self.assertContains(response, "too similar to the username")