'Non-interactive makemigrations fails when a default is missing on a
field changed to not-null.'

def test_makemigrations_non_interactive_not_null_alteration(self):

    class Author(models.Model, ):
        name = models.CharField(max_length=255)
        slug = models.SlugField()
        age = models.IntegerField(default=0)
        class Meta:
            app_label = 'migrations'
    out = io.StringIO()
    with self.temporary_migration_module(module='migrations.test_migrations'):
        call_command('makemigrations', 'migrations', interactive=False, stdout=out)
    self.assertIn('Alter    field    slug    on    author', out.getvalue())
