Add test-case for sort models behavior, refs #2893

This is working well, need to adapt the code for the delete instance
code.

tests/db_tests.py

@@ -700,6 +700,35 @@ class E(Model):
  sorted_models = sort_models(list_of_models)
  self.assertEqual(sorted_models, models)
 
+ def test_sort_models_multi_fk(self):
+ class Inventory(Model):
+ pass
+ class Sheet(Model):
+ inventory = ForeignKeyField(Inventory)
+ class Program(Model):
+ inventory = ForeignKeyField(Inventory)
+ class ProgramSheet(Model):
+ program = ForeignKeyField(Program)
+ sheet = ForeignKeyField(Sheet)
+ class ProgramPart(Model):
+ program_sheet = ForeignKeyField(ProgramSheet)
+ class Offal(Model):
+ program_sheet = ForeignKeyField(ProgramSheet)
+ sheet = ForeignKeyField(Sheet)
+
+ M = [Inventory, Sheet, Program, ProgramSheet, ProgramPart, Offal]
+ sorted_models = sort_models(M)
+ self.assertEqual(sorted_models, [
+ Inventory,
+ Program,
+ Sheet,
+ ProgramSheet,
+ Offal,
+ ProgramPart,
+ ])
+ for list_of_models in permutations(M):
+ self.assertEqual(sort_models(list_of_models), sorted_models)
+
 
 class TestDBProxy(BaseTestCase):
  def test_proxy_context_manager(self):