Fixed #24900 -- Allowed migrating backward to squashed migrations.

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/migrations/test_commands.py b/tests/migrations/test_commands.py
index 563b1bd146..d545f125dd 100644
--- a/tests/migrations/test_commands.py
+++ b/tests/migrations/test_commands.py
@@ -980,6 +980,19 @@ class MigrateTests(MigrationTestBase):
                 # Unmigrate everything.
                 call_command('migrate', 'migrations', 'zero', verbosity=0)
 
+    @override_settings(MIGRATION_MODULES={'migrations': 'migrations.test_migrations_squashed'})
+    def test_migrate_backward_to_squashed_migration(self):
+        try:
+            call_command('migrate', 'migrations', '0001_squashed_0002', verbosity=0)
+            self.assertTableExists('migrations_author')
+            self.assertTableExists('migrations_book')
+            call_command('migrate', 'migrations', '0001_initial', verbosity=0)
+            self.assertTableExists('migrations_author')
+            self.assertTableNotExists('migrations_book')
+        finally:
+            # Unmigrate everything.
+            call_command('migrate', 'migrations', 'zero', verbosity=0)
+
     @override_settings(MIGRATION_MODULES={'migrations': 'migrations.test_migrations'})
     def test_migrate_inconsistent_history(self):
         """