'field-level through checking is working. This should manage to collapse
model Foo to nonexistence, and model Bar to a single IntegerField
called "width".'

def test_optimize_through_fields(self):

    self.assertOptimizesTo([migrations.CreateModel('Foo', [('name', models.CharField(max_length=255))]), migrations.CreateModel('Bar', [('size', models.IntegerField())]), migrations.AddField('Foo', 'age', models.IntegerField()), migrations.AddField('Bar', 'width', models.IntegerField()), migrations.AlterField('Foo', 'age', models.IntegerField()), migrations.RenameField('Bar', 'size', 'dimensions'), migrations.RemoveField('Foo', 'age'), migrations.RenameModel('Foo', 'Phou'), migrations.RemoveField('Bar', 'dimensions'), migrations.RenameModel('Phou', 'Fou'), migrations.DeleteModel('Fou')], [migrations.CreateModel('Bar', [('width', models.IntegerField())])])
