text: import pickle
  
  from django.core.exceptions import ValidationError
  from django.forms import BooleanField
  from django.test import SimpleTestCase
  
  
  class BooleanFieldTest(SimpleTestCase):
      def test_booleanfield_clean_1(self):
          f = BooleanField()
          with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
              f.clean("")
          with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
              f.clean(None)
          self.assertTrue(f.clean(True))
          with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
              f.clean(False)
          self.assertTrue(f.clean(1))
          with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
              f.clean(0)
          self.assertTrue(f.clean("Django rocks"))
          self.assertTrue(f.clean("True"))
          with self.assertRaisesMessage(ValidationError, "'This field is required.'"):
              f.clean("False")
  
      def test_booleanfield_clean_2(self):
          f = BooleanField(required=False)
          self.assertIs(f.clean(""), False)
          self.assertIs(f.clean(None), False)
          self.assertIs(f.clean(True), True)
          self.assertIs(f.clean(False), False)
          self.assertIs(f.clean(1), True)
          self.assertIs(f.clean(0), False)
          self.assertIs(f.clean("1"), True)
          self.assertIs(f.clean("0"), False)
          self.assertIs(f.clean("Django rocks"), True)
          self.assertIs(f.clean("False"), False)
          self.assertIs(f.clean("false"), False)
          self.assertIs(f.clean("FaLsE"), False)
  
      def test_boolean_picklable(self):
          self.assertIsInstance(pickle.loads(pickle.dumps(BooleanField())), BooleanField)
  
      def test_booleanfield_changed(self):
          f = BooleanField()
          self.assertFalse(f.has_changed(None, None))
          self.assertFalse(f.has_changed(None, ""))
          self.assertFalse(f.has_changed("", None))
          self.assertFalse(f.has_changed("", ""))
          self.assertTrue(f.has_changed(False, "on"))
          self.assertFalse(f.has_changed(True, "on"))
          self.assertTrue(f.has_changed(True, ""))
          # Initial value may have mutated to a string due to show_hidden_initial (#19537)
          self.assertTrue(f.has_changed("False", "on"))
          # HiddenInput widget sends string values for boolean but doesn't clean them in value_from_datadict
          self.assertFalse(f.has_changed(False, "False"))
          self.assertFalse(f.has_changed(True, "True"))
          self.assertTrue(f.has_changed(False, "True"))
          self.assertTrue(f.has_changed(True, "False"))
  
      def test_disabled_has_changed(self):
          f = BooleanField(disabled=True)
          self.assertIs(f.has_changed("True", "False"), False)
  