from django.db import transaction

from django.test import TestCase

from .models import FloatModel

class TestFloatField(TestCase):

    def test_float_validates_object(self):

        instance = FloatModel(size=2.5)

        # Try setting float field to unsaved object

        instance.size = instance

        with transaction.atomic():

            with self.assertRaises(TypeError):

                instance.save()

        # Set value to valid and save

        instance.size = 2.5

        instance.save()

        self.assertTrue(instance.id)

        # Set field to object on saved instance

        instance.size = instance

        msg = (

            "Tried to update field model_fields.FloatModel.size with a model "

            "instance, %r. Use a value compatible with FloatField."

        ) % instance

        with transaction.atomic():

            with self.assertRaisesMessage(TypeError, msg):

                instance.save()

        # Try setting field to object on retrieved object

        obj = FloatModel.objects.get(pk=instance.id)

        obj.size = obj

        with self.assertRaisesMessage(TypeError, msg):

            obj.save()

    def test_invalid_value(self):

        tests = [

            (TypeError, ()),

            (TypeError, []),

            (TypeError, {}),

            (TypeError, set()),

            (TypeError, object()),

            (TypeError, complex()),

            (ValueError, "non-numeric string"),

            (ValueError, b"non-numeric byte-string"),

        ]

        for exception, value in tests:

            with self.subTest(value):

                msg = "Field 'size' expected a number but got %r." % (value,)

                with self.assertRaisesMessage(exception, msg):

                    FloatModel.objects.create(size=value)