text: from wtforms import Form, IntegerField, StringField
  from wtforms.validators import Optional
  import pytest
  
  
  class MyForm(Form):
      a = IntegerField(validators=[Optional()])
      b = StringField()
      c = StringField(default='c')
  
  
  class MyCallableForm(Form):
      a = IntegerField(validators=[Optional()])
      b = StringField()
      c = StringField(default=lambda: 'c')
  
  
  @pytest.mark.parametrize('cls', [MyForm, MyCallableForm])
  def test_object_defaults(cls):
      class SomeClass(object):
          a = 1
          b = 'someone'
  
      form = cls.from_json(obj=SomeClass())
      assert form.data == {'a': 1, 'b': 'someone', 'c': 'c'}
  
  
  @pytest.mark.parametrize('cls', [MyForm, MyCallableForm])
  def test_formdata_defaults(cls):
      form = cls.from_json({'a': 1, 'b': 'something'})
      assert form.data == {'a': 1, 'b': 'something', 'c': 'c'}
  