/tests/regressiontests/model_fields/imagefield.py

import os
import shutil

from django.core.files import File
from django.core.files.base import ContentFile
from django.core.files.images import ImageFile
from django.test import TestCase

from models import Image, Person, PersonWithHeight, PersonWithHeightAndWidth, \
        PersonDimensionsFirst, PersonTwoImages, TestImageFieldFile


# If PIL available, do these tests.
if Image:

    from models import temp_storage_dir


    class ImageFieldTestMixin(object):
        """
        Mixin class to provide common functionality to ImageField test classes.
        """

        # Person model to use for tests.
        PersonModel = PersonWithHeightAndWidth
        # File class to use for file instances.
        File = ImageFile

        def setUp(self):
            """
            Creates a pristine temp directory (or deletes and recreates if it
            already exists) that the model uses as its storage directory.

            Sets up two ImageFile instances for use in tests.
            """
            if os.path.exists(temp_storage_dir):
                shutil.rmtree(temp_storage_dir)
            os.mkdir(temp_storage_dir)

            file_path1 = os.path.join(os.path.dirname(__file__), "4x8.png")
            self.file1 = self.File(open(file_path1, 'rb'))

            file_path2 = os.path.join(os.path.dirname(__file__), "8x4.png")
            self.file2 = self.File(open(file_path2, 'rb'))

        def tearDown(self):
            """
            Removes temp directory and all its contents.
            """
            shutil.rmtree(temp_storage_dir)

        def check_dimensions(self, instance, width, height,
                             field_name='mugshot'):
            """
            Asserts that the given width and height values match both the
            field's height and width attributes and the height and width fields
            (if defined) the image field is caching to.

            Note, this method will check for dimension fields named by adding
            "_width" or "_height" to the name of the ImageField.  So, the
            models used in these tests must have their fields named
            accordingly.

            By default, we check the field named "mugshot", but this can be
            specified by passing the field_name parameter.
            """
            field = getattr(instance, field_name)
            # Check height/width attributes of field.
            if width is None and height is None:
                self.assertRaises(ValueError, getattr, field, 'width')
                self.assertRaises(ValueError, getattr, field, 'height')
            else:
                self.assertEqual(field.width, width)
                self.assertEqual(field.height, height)

            # Check height/width fields of model, if defined.
            width_field_name = field_name + '_width'
            if hasattr(instance, width_field_name):
                self.assertEqual(getattr(instance, width_field_name), width)
            height_field_name = field_name + '_height'
            if hasattr(instance, height_field_name):
                self.assertEqual(getattr(instance, height_field_name), height)


    class ImageFieldTests(ImageFieldTestMixin, TestCase):
        """
        Tests for ImageField that don't need to be run with each of the
        different test model classes.
        """

        def test_equal_notequal_hash(self):
            """
            Bug #9786: Ensure '==' and '!=' work correctly.
            Bug #9508: make sure hash() works as expected (equal items must
            hash to the same value).
            """
            # Create two Persons with different mugshots.
            p1 = self.PersonModel(name="Joe")
            p1.mugshot.save("mug", self.file1)
            p2 = self.PersonModel(name="Bob")
            p2.mugshot.save("mug", self.file2)
            self.assertEqual(p1.mugshot == p2.mugshot, False)
            self.assertEqual(p1.mugshot != p2.mugshot, True)

            # Test again with an instance fetched from the db.
            p1_db = self.PersonModel.objects.get(name="Joe")
            self.assertEqual(p1_db.mugshot == p2.mugshot, False)
            self.assertEqual(p1_db.mugshot != p2.mugshot, True)

            # Instance from db should match the local instance.
            self.assertEqual(p1_db.mugshot == p1.mugshot, True)
            self.assertEqual(hash(p1_db.mugshot), hash(p1.mugshot))
            self.assertEqual(p1_db.mugshot != p1.mugshot, False)

        def test_instantiate_missing(self):
            """
            If the underlying file is unavailable, still create instantiate the
            object without error.
            """
            p = self.PersonModel(name="Joan")
            p.mugshot.save("shot", self.file1)
            p = self.PersonModel.objects.get(name="Joan")
            path = p.mugshot.path
            shutil.move(path, path + '.moved')
            p2 = self.PersonModel.objects.get(name="Joan")

        def test_delete_when_missing(self):
            """
            Bug #8175: correctly delete an object where the file no longer
            exists on the file system.
            """
            p = self.PersonModel(name="Fred")
            p.mugshot.save("shot", self.file1)
            os.remove(p.mugshot.path)
            p.delete()

        def test_size_method(self):
            """
            Bug #8534: FileField.size should not leave the file open.
            """
            p = self.PersonModel(name="Joan")
            p.mugshot.save("shot", self.file1)

            # Get a "clean" model instance
            p = self.PersonModel.objects.get(name="Joan")
            # It won't have an opened file.
            self.assertEqual(p.mugshot.closed, True)

            # After asking for the size, the file should still be closed.
            _ = p.mugshot.size
            self.assertEqual(p.mugshot.closed, True)

        def test_pickle(self):
            """
            Tests that ImageField can be pickled, unpickled, and that the
            image of the unpickled version is the same as the original.
            """
            import pickle

            p = Person(name="Joe")
            p.mugshot.save("mug", self.file1)
            dump = pickle.dumps(p)

            p2 = Person(name="Bob")
            p2.mugshot = self.file1

            loaded_p = pickle.loads(dump)
            self.assertEqual(p.mugshot, loaded_p.mugshot)


    class ImageFieldTwoDimensionsTests(ImageFieldTestMixin, TestCase):
        """
        Tests behavior of an ImageField and its dimensions fields.
        """

        def test_constructor(self):
            """
            Tests assigning an image field through the model's constructor.
            """
            p = self.PersonModel(name='Joe', mugshot=self.file1)
            self.check_dimensions(p, 4, 8)
            p.save()
            self.check_dimensions(p, 4, 8)

        def test_image_after_constructor(self):
            """
            Tests behavior when image is not passed in constructor.
            """
            p = self.PersonModel(name='Joe')
            # TestImageField value will default to being an instance of its
            # attr_class, a  TestImageFieldFile, with name == None, which will
            # cause it to evaluate as False.
            self.assertEqual(isinstance(p.mugshot, TestImageFieldFile), True)
            self.assertEqual(bool(p.mugshot), False)

            # Test setting a fresh created model instance.
            p = self.PersonModel(name='Joe')
            p.mugshot = self.file1
            self.check_dimensions(p, 4, 8)

        def test_create(self):
            """
            Tests assigning an image in Manager.create().
            """
            p = self.PersonModel.objects.create(name='Joe', mugshot=self.file1)
            self.check_dimensions(p, 4, 8)

        def test_default_value(self):
            """
            Tests that the default value for an ImageField is an instance of
            the field's attr_class (TestImageFieldFile in this case) with no
            name (name set to None).
            """
            p = self.PersonModel()
            self.assertEqual(isinstance(p.mugshot, TestImageFieldFile), True)
            self.assertEqual(bool(p.mugshot), False)

        def test_assignment_to_None(self):
            """
            Tests that assigning ImageField to None clears dimensions.
            """
            p = self.PersonModel(name='Joe', mugshot=self.file1)
            self.check_dimensions(p, 4, 8)

            # If image assigned to None, dimension fields should be cleared.
            p.mugshot = None
            self.check_dimensions(p, None, None)

            p.mugshot = self.file2
            self.check_dimensions(p, 8, 4)

        def test_field_save_and_delete_methods(self):
            """
            Tests assignment using the field's save method and deletion using
            the field's delete method.
            """
            p = self.PersonModel(name='Joe')
            p.mugshot.save("mug", self.file1)
            self.check_dimensions(p, 4, 8)

            # A new file should update dimensions.
            p.mugshot.save("mug", self.file2)
            self.check_dimensions(p, 8, 4)

            # Field and dimensions should be cleared after a delete.
            p.mugshot.delete(save=False)
            self.assertEqual(p.mugshot, None)
            self.check_dimensions(p, None, None)

        def test_dimensions(self):
            """
            Checks that dimensions are updated correctly in various situations.
            """
            p = self.PersonModel(name='Joe')

            # Dimensions should get set if file is saved.
            p.mugshot.save("mug", self.file1)
            self.check_dimensions(p, 4, 8)

            # Test dimensions after fetching from database.
            p = self.PersonModel.objects.get(name='Joe')
            # Bug 11084: Dimensions should not get recalculated if file is
            # coming from the database.  We test this by checking if the file
            # was opened.
            self.assertEqual(p.mugshot.was_opened, False)
            self.check_dimensions(p, 4, 8)
            # After checking dimensions on the image field, the file will have
            # opened.
            self.assertEqual(p.mugshot.was_opened, True)
            # Dimensions should now be cached, and if we reset was_opened and
            # check dimensions again, the file should not have opened.
            p.mugshot.was_opened = False
            self.check_dimensions(p, 4, 8)
            self.assertEqual(p.mugshot.was_opened, False)

            # If we assign a new image to the instance, the dimensions should
            # update.
            p.mugshot = self.file2
            self.check_dimensions(p, 8, 4)
            # Dimensions were recalculated, and hence file should have opened.
            self.assertEqual(p.mugshot.was_opened, True)


    class ImageFieldNoDimensionsTests(ImageFieldTwoDimensionsTests):
        """
        Tests behavior of an ImageField with no dimension fields.
        """

        PersonModel = Person


    class ImageFieldOneDimensionTests(ImageFieldTwoDimensionsTests):
        """
        Tests behavior of an ImageField with one dimensions field.
        """

        PersonModel = PersonWithHeight


    class ImageFieldDimensionsFirstTests(ImageFieldTwoDimensionsTests):
        """
        Tests behavior of an ImageField where the dimensions fields are
        defined before the ImageField.
        """

        PersonModel = PersonDimensionsFirst


    class ImageFieldUsingFileTests(ImageFieldTwoDimensionsTests):
        """
        Tests behavior of an ImageField when assigning it a File instance
        rather than an ImageFile instance.
        """

        PersonModel = PersonDimensionsFirst
        File = File


    class TwoImageFieldTests(ImageFieldTestMixin, TestCase):
        """
        Tests a model with two ImageFields.
        """

        PersonModel = PersonTwoImages

        def test_constructor(self):
            p = self.PersonModel(mugshot=self.file1, headshot=self.file2)
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')
            p.save()
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')

        def test_create(self):
            p = self.PersonModel.objects.create(mugshot=self.file1,
                                                headshot=self.file2)
            self.check_dimensions(p, 4, 8)
            self.check_dimensions(p, 8, 4, 'headshot')

        def test_assignment(self):
            p = self.PersonModel()
            self.check_dimensions(p, None, None, 'mugshot')
            self.check_dimensions(p, None, None, 'headshot')

            p.mugshot = self.file1
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, None, None, 'headshot')
            p.headshot = self.file2
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')

            # Clear the ImageFields one at a time.
            p.mugshot = None
            self.check_dimensions(p, None, None, 'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')
            p.headshot = None
            self.check_dimensions(p, None, None, 'mugshot')
            self.check_dimensions(p, None, None, 'headshot')

        def test_field_save_and_delete_methods(self):
            p = self.PersonModel(name='Joe')
            p.mugshot.save("mug", self.file1)
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, None, None, 'headshot')
            p.headshot.save("head", self.file2)
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')

            # We can use save=True when deleting the image field with null=True
            # dimension fields and the other field has an image.
            p.headshot.delete(save=True)
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, None, None, 'headshot')
            p.mugshot.delete(save=False)
            self.check_dimensions(p, None, None, 'mugshot')
            self.check_dimensions(p, None, None, 'headshot')

        def test_dimensions(self):
            """
            Checks that dimensions are updated correctly in various situations.
            """
            p = self.PersonModel(name='Joe')

            # Dimensions should get set for the saved file.
            p.mugshot.save("mug", self.file1)
            p.headshot.save("head", self.file2)
            self.check_dimensions(p, 4, 8, 'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')

            # Test dimensions after fetching from database.
            p = self.PersonModel.objects.get(name='Joe')
            # Bug 11084: Dimensions should not get recalculated if file is
            # coming from the database.  We test this by checking if the file
            # was opened.
            self.assertEqual(p.mugshot.was_opened, False)
            self.assertEqual(p.headshot.was_opened, False)
            self.check_dimensions(p, 4, 8,'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')
            # After checking dimensions on the image fields, the files will
            # have been opened.
            self.assertEqual(p.mugshot.was_opened, True)
            self.assertEqual(p.headshot.was_opened, True)
            # Dimensions should now be cached, and if we reset was_opened and
            # check dimensions again, the file should not have opened.
            p.mugshot.was_opened = False
            p.headshot.was_opened = False
            self.check_dimensions(p, 4, 8,'mugshot')
            self.check_dimensions(p, 8, 4, 'headshot')
            self.assertEqual(p.mugshot.was_opened, False)
            self.assertEqual(p.headshot.was_opened, False)

            # If we assign a new image to the instance, the dimensions should
            # update.
            p.mugshot = self.file2
            p.headshot = self.file1
            self.check_dimensions(p, 8, 4, 'mugshot')
            self.check_dimensions(p, 4, 8, 'headshot')
            # Dimensions were recalculated, and hence file should have opened.
            self.assertEqual(p.mugshot.was_opened, True)
            self.assertEqual(p.headshot.was_opened, True)