Fixed #20579 -- Improved TransactionTestCase.available_apps.

Also moved its documentation to the 'advanced' section. It doesn't
belong to the 'overview'. Same for TransactionTestCase.reset_sequences.

When available_apps is set, after a TransactionTestCase, the database
is now totally empty. post_syncdb is fired at the beginning of the next
TransactionTestCase.

Refs #20483.

1 files changed, 17 insertions, 11 deletions

diff --git a/django/core/management/commands/flush.py b/django/core/management/commands/flush.py
index 7054187e45..95dd634d08 100644
--- a/django/core/management/commands/flush.py
+++ b/django/core/management/commands/flush.py
@@ -32,9 +32,10 @@ class Command(NoArgsCommand):
         connection = connections[db]
         verbosity = int(options.get('verbosity'))
         interactive = options.get('interactive')
-        # 'reset_sequences' and 'allow_cascade' are stealth options
+        # The following are stealth options used by Django's internals.
         reset_sequences = options.get('reset_sequences', True)
         allow_cascade = options.get('allow_cascade', False)
+        inhibit_post_syncdb = options.get('inhibit_post_syncdb', False)
 
         self.style = no_style()
 
@@ -75,16 +76,9 @@ Are you sure you want to do this?
                     "Hint: Look at the output of 'django-admin.py sqlflush'. That's the SQL this command wasn't able to run.\n"
                     "The full error: %s") % (connection.settings_dict['NAME'], e)
                 six.reraise(CommandError, CommandError(new_msg), sys.exc_info()[2])
-            # Emit the post sync signal. This allows individual
-            # applications to respond as if the database had been
-            # sync'd from scratch.
-            all_models = []
-            for app in models.get_apps():
-                all_models.extend([
-                    m for m in models.get_models(app, include_auto_created=True)
-                    if router.allow_syncdb(db, m)
-                ])
-            emit_post_sync_signal(set(all_models), verbosity, interactive, db)
+
+            if not inhibit_post_syncdb:
+                self.emit_post_syncdb(verbosity, interactive, db)
 
             # Reinstall the initial_data fixture.
             if options.get('load_initial_data'):
@@ -93,3 +87,15 @@ Are you sure you want to do this?
 
         else:
             self.stdout.write("Flush cancelled.\n")
+
+    @staticmethod
+    def emit_post_syncdb(verbosity, interactive, database):
+        # Emit the post sync signal. This allows individual applications to
+        # respond as if the database had been sync'd from scratch.
+        all_models = []
+        for app in models.get_apps():
+            all_models.extend([
+                m for m in models.get_models(app, include_auto_created=True)
+                if router.allow_syncdb(database, m)
+            ])
+        emit_post_sync_signal(set(all_models), verbosity, interactive, database)