path: root/unittest/metadata.py

# -*- coding: utf-8 -*-

# ******************************************************************************
#
# Copyright (C) 2009 Olivier Tilloy <olivier@tilloy.net>
#
# This file is part of the pyexiv2 distribution.
#
# pyexiv2 is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# pyexiv2 is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with pyexiv2; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
#
# Author: Olivier Tilloy <olivier@tilloy.net>
#
# ******************************************************************************

import unittest
from pyexiv2 import ImageMetadata, ExifTag, IptcTag, XmpTag
import datetime


class ImageMock(object):

    def __init__(self, filename):
        self.filename = filename
        self.read = False
        self.written = False
        self.tags = {'exif': {}, 'iptc': {}, 'xmp': {}}

    def readMetadata(self):
        self.read = True

    def writeMetadata(self):
        self.written = True

    def exifKeys(self):
        return self.tags['exif'].keys()

    def getExifTag(self, key):
        return self.tags['exif'][key]

    def setExifTagValue(self, key, value):
        self.tags['exif'][key] = value

    def deleteExifTag(self, key):
        try:
            del self.tags['exif'][key]
        except KeyError:
            pass

    def iptcKeys(self):
        return self.tags['iptc'].keys()

    def getIptcTag(self, key):
        return self.tags['iptc'][key]

    def setIptcTagValues(self, key, values):
        self.tags['iptc'][key] = values

    def deleteIptcTag(self, key):
        try:
            del self.tags['iptc'][key]
        except KeyError:
            pass

    def xmpKeys(self):
        return self.tags['xmp'].keys()

    def getXmpTag(self, key):
        return self.tags['xmp'][key]

    def setXmpTagValue(self, key, value):
        self.tags['xmp'][key] = value

    def deleteXmpTag(self, key):
        try:
            del self.tags['xmp'][key]
        except KeyError:
            pass


class TestImageMetadata(unittest.TestCase):

    def setUp(self):
        self.metadata = ImageMetadata('nofile')
        self.metadata._instantiate_image = lambda filename: ImageMock(filename)

    def _set_exif_tags(self):
        tags = {}
        tags['Exif.Image.Make'] = \
            ('Exif.Image.Make', 'Make', 'Manufacturer', 'blabla', 'Ascii',
             'EASTMAN KODAK COMPANY', 'EASTMAN KODAK COMPANY')
        tags['Exif.Image.DateTime'] = \
            ('Exif.Image.DateTime', 'DateTime', 'Date and Time', 'blabla',
             'Ascii', '2009:02:09 13:33:20', '2009:02:09 13:33:20')
        tags['Exif.Photo.ExifVersion'] = \
            ('Exif.Photo.ExifVersion', 'ExifVersion', 'Exif Version', 'blabla',
             'Undefined', '48 50 50 49 ', '2.21')
        self.metadata._image.tags['exif'] = tags

    def _set_iptc_tags(self):
        tags = {}
        tags['Iptc.Application2.Caption'] = \
            ('Iptc.Application2.Caption', 'Caption', 'Caption',
             'A textual description of the object data.', 'String',
             ['blabla'])
        tags['Iptc.Application2.DateCreated'] = \
            ('Iptc.Application2.DateCreated', 'DateCreated', 'Date Created',
             'Represented in the form CCYYMMDD to designate the date the ' \
             'intellectual content of the object data was created rather ' \
             'than the date of the creation of the physical representation. ' \
             'Follows ISO 8601 standard.', 'Date', ['2004-07-13'])
        self.metadata._image.tags['iptc'] = tags

    def _set_xmp_tags(self):
        tags = {}
        tags['Xmp.dc.format'] = \
            ('Xmp.dc.format', 'format', 'Format', 'The file format used when ' \
             'saving the resource. Tools and applications should set this ' \
             'property to the save format of the data. It may include ' \
             'appropriate qualifiers.', 'MIMEType', 'image/jpeg')
        tags['Xmp.dc.subject'] = \
            ('Xmp.dc.subject', 'subject', 'Subject', 'An unordered array of ' \
             'descriptive phrases or keywords that specify the topic of the ' \
             'content of the resource.', 'bag Text', 'image, test, pyexiv2')
        tags['Xmp.xmp.CreateDate'] = \
            ('Xmp.xmp.CreateDate', 'CreateDate', 'Create Date',
             'The date and time the resource was originally created.', 'Date',
             '2005-09-07T15:07:40-07:00')
        tags['Xmp.xmpMM.DocumentID'] = \
            ('Xmp.xmpMM.DocumentID', 'DocumentID', 'Document ID',
             'The common identifier for all versions and renditions of a ' \
             'document. It should be based on a UUID; see Document and ' \
             'Instance IDs below.', 'URI',
             'uuid:9A3B7F52214211DAB6308A7391270C13')
        self.metadata._image.tags['xmp'] = tags

    ######################
    # Test general methods
    ######################

    def test_read(self):
        self.assertEqual(self.metadata._image, None)
        self.metadata.read()
        self.failIfEqual(self.metadata._image, None)
        self.failUnless(self.metadata._image.read)

    def test_write(self):
        self.metadata.read()
        self.failIf(self.metadata._image.written)
        self.metadata.write()
        self.failUnless(self.metadata._image.written)

    ###########################
    # Test EXIF-related methods
    ###########################

    def test_exif_keys(self):
        self.metadata.read()
        self._set_exif_tags()
        self.assertEqual(self.metadata._keys['exif'], None)
        keys = self.metadata.exif_keys
        self.assertEqual(len(keys), 3)
        self.assertEqual(self.metadata._keys['exif'], keys)

    def test_get_exif_tag(self):
        self.metadata.read()
        self._set_exif_tags()
        self.assertEqual(self.metadata._tags['exif'], {})
        # Get an existing tag
        key = 'Exif.Image.Make'
        tag = self.metadata._get_exif_tag(key)
        self.assertEqual(type(tag), ExifTag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['exif'][key], tag)
        # Try to get an nonexistent tag
        key = 'Exif.Photo.Sharpness'
        self.failUnlessRaises(KeyError, self.metadata._get_exif_tag, key)

    def test_set_exif_tag_wrong(self):
        self.metadata.read()
        self._set_exif_tags()
        self.assertEqual(self.metadata._tags['exif'], {})
        # Try to set a tag with wrong type
        tag = 'Not an exif tag'
        self.failUnlessRaises(TypeError, self.metadata._set_exif_tag, tag)
        self.assertEqual(self.metadata._tags['exif'], {})

    def test_set_exif_tag_create(self):
        self.metadata.read()
        self._set_exif_tags()
        self.assertEqual(self.metadata._tags['exif'], {})
        # Create a new tag
        tag = ExifTag('Exif.Thumbnail.Orientation', 'Orientation',
                      'Orientation', 'The image orientation viewed in terms ' \
                      'of rows and columns.', 'Short', '1', 'top, left')
        self.assertEqual(tag.metadata, None)
        self.metadata._set_exif_tag(tag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['exif'], {tag.key: tag})
        self.assert_(self.metadata._image.tags['exif'].has_key(tag.key))
        self.assertEqual(self.metadata._image.tags['exif'][tag.key],
                         tag.raw_value)

    def test_set_exif_tag_overwrite(self):
        self.metadata.read()
        self._set_exif_tags()
        self.assertEqual(self.metadata._tags['exif'], {})
        # Overwrite an existing tag
        tag = ExifTag('Exif.Image.DateTime', 'DateTime', 'Date and Time',
                      'blabla', 'Ascii', '2009:03:20 20:32:00',
                      '2009:03:20 20:32:00')
        self.assertEqual(tag.metadata, None)
        self.metadata._set_exif_tag(tag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['exif'], {tag.key: tag})
        self.assert_(self.metadata._image.tags['exif'].has_key(tag.key))
        self.assertEqual(self.metadata._image.tags['exif'][tag.key],
                         tag.raw_value)

    def test_set_exif_tag_overwrite_already_cached(self):
        self.metadata.read()
        self._set_exif_tags()
        self.assertEqual(self.metadata._tags['exif'], {})
        # Overwrite an existing tag already cached
        key = 'Exif.Photo.ExifVersion'
        tag = self.metadata._get_exif_tag(key)
        self.assertEqual(self.metadata._tags['exif'][key], tag)
        new_tag = ExifTag(key, 'ExifVersion', 'Exif Version', 'blabla',
                          'Undefined', '48 50 50 48 ', '2.20')
        self.assertEqual(new_tag.metadata, None)
        self.metadata._set_exif_tag(new_tag)
        self.assertEqual(new_tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['exif'], {key: new_tag})
        self.assert_(self.metadata._image.tags['exif'].has_key(key))
        # Special case where the formatted value is used instead of the raw
        # value.
        self.assertEqual(self.metadata._image.tags['exif'][key], new_tag.fvalue)

    def test_set_exif_tag_value_inexistent(self):
        self.metadata.read()
        self._set_exif_tags()
        key = 'Exif.Photo.ExposureTime'
        value = '1/500'
        self.failUnlessRaises(KeyError, self.metadata._set_exif_tag_value,
                              key, value)

    def test_set_exif_tag_value_wrong_type(self):
        self.metadata.read()
        self._set_exif_tags()
        key = 'Exif.Image.DateTime'
        value = datetime.datetime(2009, 3, 24, 9, 37, 36)
        self.failUnlessRaises(TypeError, self.metadata._set_exif_tag_value,
                              key, value)

    def test_set_exif_tag_value(self):
        self.metadata.read()
        self._set_exif_tags()
        key = 'Exif.Image.DateTime'
        tag = self.metadata._get_exif_tag(key)
        value = '2009:03:24 09:37:36'
        self.failIfEqual(self.metadata._image.tags['exif'][key], value)
        self.metadata._set_exif_tag_value(key, value)
        self.assertEqual(self.metadata._image.tags['exif'][key], value)

    def test_delete_exif_tag_inexistent(self):
        self.metadata.read()
        self._set_exif_tags()
        key = 'Exif.Image.Artist'
        self.failUnlessRaises(KeyError, self.metadata._delete_exif_tag, key)

    def test_delete_exif_tag_not_cached(self):
        self.metadata.read()
        self._set_exif_tags()
        key = 'Exif.Image.DateTime'
        self.assertEqual(self.metadata._tags['exif'], {})
        self.assert_(self.metadata._image.tags['exif'].has_key(key))
        self.metadata._delete_exif_tag(key)
        self.assertEqual(self.metadata._tags['exif'], {})
        self.failIf(self.metadata._image.tags['exif'].has_key(key))

    def test_delete_exif_tag_cached(self):
        self.metadata.read()
        self._set_exif_tags()
        key = 'Exif.Image.DateTime'
        self.assert_(self.metadata._image.tags['exif'].has_key(key))
        tag = self.metadata._get_exif_tag(key)
        self.assertEqual(self.metadata._tags['exif'][key], tag)
        self.metadata._delete_exif_tag(key)
        self.assertEqual(self.metadata._tags['exif'], {})
        self.failIf(self.metadata._image.tags['exif'].has_key(key))

    ###########################
    # Test IPTC-related methods
    ###########################

    def test_iptc_keys(self):
        self.metadata.read()
        self._set_iptc_tags()
        self.assertEqual(self.metadata._keys['iptc'], None)
        keys = self.metadata.iptc_keys
        self.assertEqual(len(keys), 2)
        self.assertEqual(self.metadata._keys['iptc'], keys)

    def test_get_iptc_tag(self):
        self.metadata.read()
        self._set_iptc_tags()
        self.assertEqual(self.metadata._tags['iptc'], {})
        # Get an existing tag
        key = 'Iptc.Application2.DateCreated'
        tag = self.metadata._get_iptc_tag(key)
        self.assertEqual(type(tag), IptcTag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['iptc'][key], tag)
        # Try to get an nonexistent tag
        key = 'Iptc.Application2.Copyright'
        self.failUnlessRaises(KeyError, self.metadata._get_iptc_tag, key)

    def test_set_iptc_tag_wrong(self):
        self.metadata.read()
        self._set_iptc_tags()
        self.assertEqual(self.metadata._tags['iptc'], {})
        # Try to set a tag with wrong type
        tag = 'Not an iptc tag'
        self.failUnlessRaises(TypeError, self.metadata._set_iptc_tag, tag)
        self.assertEqual(self.metadata._tags['iptc'], {})

    def test_set_iptc_tag_create(self):
        self.metadata.read()
        self._set_iptc_tags()
        self.assertEqual(self.metadata._tags['iptc'], {})
        # Create a new tag
        tag = IptcTag('Iptc.Application2.Writer', 'Writer', 'Writer',
                      'Identification of the name of the person involved in ' \
                      'the writing, editing or correcting the object data or ' \
                      'caption/abstract.', 'String', ['Nobody'])
        self.assertEqual(tag.metadata, None)
        self.metadata._set_iptc_tag(tag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['iptc'], {tag.key: tag})
        self.assert_(self.metadata._image.tags['iptc'].has_key(tag.key))
        self.assertEqual(self.metadata._image.tags['iptc'][tag.key],
                         tag.raw_value)

    def test_set_iptc_tag_overwrite(self):
        self.metadata.read()
        self._set_iptc_tags()
        self.assertEqual(self.metadata._tags['iptc'], {})
        # Overwrite an existing tag
        tag = IptcTag('Iptc.Application2.Caption', 'Caption', 'Caption',
                      'A textual description of the object data.', 'String',
                      ['A picture.'])
        self.assertEqual(tag.metadata, None)
        self.metadata._set_iptc_tag(tag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['iptc'], {tag.key: tag})
        self.assert_(self.metadata._image.tags['iptc'].has_key(tag.key))
        self.assertEqual(self.metadata._image.tags['iptc'][tag.key],
                         tag.raw_value)

    def test_set_iptc_tag_overwrite_already_cached(self):
        self.metadata.read()
        self._set_iptc_tags()
        self.assertEqual(self.metadata._tags['iptc'], {})
        # Overwrite an existing tag already cached
        key = 'Iptc.Application2.Caption'
        tag = self.metadata._get_iptc_tag(key)
        self.assertEqual(self.metadata._tags['iptc'][key], tag)
        new_tag = IptcTag(key, 'Caption', 'Caption',
                      'A textual description of the object data.', 'String',
                      ['A picture.'])
        self.assertEqual(new_tag.metadata, None)
        self.metadata._set_iptc_tag(new_tag)
        self.assertEqual(new_tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['iptc'], {key: new_tag})
        self.assert_(self.metadata._image.tags['iptc'].has_key(key))
        self.assertEqual(self.metadata._image.tags['iptc'][key],
                         new_tag.raw_value)

    def test_set_iptc_tag_values_inexistent(self):
        self.metadata.read()
        self._set_iptc_tags()
        key = 'Iptc.Application2.Urgency'
        values = ['1']
        self.failUnlessRaises(KeyError, self.metadata._set_iptc_tag_values,
                              key, values)

    def test_set_iptc_tag_values_wrong_type(self):
        self.metadata.read()
        self._set_iptc_tags()
        key = 'Iptc.Application2.DateCreated'
        value = '20090324'
        self.failUnlessRaises(TypeError, self.metadata._set_iptc_tag_values,
                              key, value)
        values = [datetime.date(2009, 3, 24)]
        self.failUnlessRaises(TypeError, self.metadata._set_iptc_tag_values,
                              key, values)

    def test_set_iptc_tag_values(self):
        self.metadata.read()
        self._set_iptc_tags()
        key = 'Iptc.Application2.DateCreated'
        tag = self.metadata._get_iptc_tag(key)
        values = ['2009-04-07']
        self.failIfEqual(self.metadata._image.tags['iptc'][key], values)
        self.metadata._set_iptc_tag_values(key, values)
        self.assertEqual(self.metadata._image.tags['iptc'][key], values)

    def test_delete_iptc_tag_inexistent(self):
        self.metadata.read()
        self._set_iptc_tags()
        key = 'Iptc.Application2.LocationCode'
        self.failUnlessRaises(KeyError, self.metadata._delete_iptc_tag, key)

    def test_delete_iptc_tag_not_cached(self):
        self.metadata.read()
        self._set_iptc_tags()
        key = 'Iptc.Application2.Caption'
        self.assertEqual(self.metadata._tags['iptc'], {})
        self.assert_(self.metadata._image.tags['iptc'].has_key(key))
        self.metadata._delete_iptc_tag(key)
        self.assertEqual(self.metadata._tags['iptc'], {})
        self.failIf(self.metadata._image.tags['iptc'].has_key(key))

    def test_delete_iptc_tag_cached(self):
        self.metadata.read()
        self._set_iptc_tags()
        key = 'Iptc.Application2.Caption'
        self.assert_(self.metadata._image.tags['iptc'].has_key(key))
        tag = self.metadata._get_iptc_tag(key)
        self.assertEqual(self.metadata._tags['iptc'][key], tag)
        self.metadata._delete_iptc_tag(key)
        self.assertEqual(self.metadata._tags['iptc'], {})
        self.failIf(self.metadata._image.tags['iptc'].has_key(key))

    ##########################
    # Test XMP-related methods
    ##########################

    def test_xmp_keys(self):
        self.metadata.read()
        self._set_xmp_tags()
        self.assertEqual(self.metadata._keys['xmp'], None)
        keys = self.metadata.xmp_keys
        self.assertEqual(len(keys), 4)
        self.assertEqual(self.metadata._keys['xmp'], keys)

    def test_get_xmp_tag(self):
        self.metadata.read()
        self._set_xmp_tags()
        self.assertEqual(self.metadata._tags['xmp'], {})
        # Get an existing tag
        key = 'Xmp.dc.subject'
        tag = self.metadata._get_xmp_tag(key)
        self.assertEqual(type(tag), XmpTag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['xmp'][key], tag)
        # Try to get an nonexistent tag
        key = 'Xmp.xmp.Label'
        self.failUnlessRaises(KeyError, self.metadata._get_xmp_tag, key)

    def test_set_xmp_tag_wrong(self):
        self.metadata.read()
        self._set_xmp_tags()
        self.assertEqual(self.metadata._tags['xmp'], {})
        # Try to set a tag with wrong type
        tag = 'Not an xmp tag'
        self.failUnlessRaises(TypeError, self.metadata._set_xmp_tag, tag)
        self.assertEqual(self.metadata._tags['xmp'], {})

    def test_set_xmp_tag_create(self):
        self.metadata.read()
        self._set_xmp_tags()
        self.assertEqual(self.metadata._tags['xmp'], {})
        # Create a new tag
        tag = XmpTag('Xmp.dc.title', 'title', 'Title', 'The title of the ' \
                     'document, or the name given to the resource. Typically,' \
                     ' it will be a name by which the resource is formally ' \
                     'known.', 'Lang Alt',
                     'lang="x-default" This is not a title, ' \
                     'lang="fr-FR" Ceci n\'est pas un titre')
        self.assertEqual(tag.metadata, None)
        self.metadata._set_xmp_tag(tag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['xmp'], {tag.key: tag})
        self.assert_(self.metadata._image.tags['xmp'].has_key(tag.key))
        self.assertEqual(self.metadata._image.tags['xmp'][tag.key],
                         tag.raw_value)

    def test_set_xmp_tag_overwrite(self):
        self.metadata.read()
        self._set_xmp_tags()
        self.assertEqual(self.metadata._tags['xmp'], {})
        # Overwrite an existing tag
        tag = XmpTag('Xmp.dc.format', 'format', 'Format', 'The file format ' \
                     'used when saving the resource. Tools and applications ' \
                     'should set this property to the save format of the ' \
                     'data. It may include appropriate qualifiers.',
                     'MIMEType', 'image/png')
        self.assertEqual(tag.metadata, None)
        self.metadata._set_xmp_tag(tag)
        self.assertEqual(tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['xmp'], {tag.key: tag})
        self.assert_(self.metadata._image.tags['xmp'].has_key(tag.key))
        self.assertEqual(self.metadata._image.tags['xmp'][tag.key],
                         tag.raw_value)

    def test_set_xmp_tag_overwrite_already_cached(self):
        self.metadata.read()
        self._set_xmp_tags()
        self.assertEqual(self.metadata._tags['xmp'], {})
        # Overwrite an existing tag already cached
        key = 'Xmp.xmp.CreateDate'
        tag = self.metadata._get_xmp_tag(key)
        self.assertEqual(self.metadata._tags['xmp'][key], tag)
        new_tag = XmpTag(key, 'CreateDate', 'Create Date',
                         'The date and time the resource was originally ' \
                         'created.', 'Date', '2009-04-21T20:07+01:00')
        self.assertEqual(new_tag.metadata, None)
        self.metadata._set_xmp_tag(new_tag)
        self.assertEqual(new_tag.metadata, self.metadata)
        self.assertEqual(self.metadata._tags['xmp'], {key: new_tag})
        self.assert_(self.metadata._image.tags['xmp'].has_key(key))
        self.assertEqual(self.metadata._image.tags['xmp'][key],
                         new_tag.raw_value)

    def test_set_xmp_tag_value_inexistent(self):
        self.metadata.read()
        self._set_xmp_tags()
        key = 'Xmp.xmp.Nickname'
        value = 'oSoMoN'
        self.failUnlessRaises(KeyError, self.metadata._set_xmp_tag_value,
                              key, value)

    def test_set_xmp_tag_value_wrong_type(self):
        self.metadata.read()
        self._set_xmp_tags()
        key = 'Xmp.xmp.CreateDate'
        value = datetime.datetime(2009, 4, 21, 20, 11, 0)
        self.failUnlessRaises(TypeError, self.metadata._set_xmp_tag_value,
                              key, value)

    def test_set_xmp_tag_value(self):
        self.metadata.read()
        self._set_xmp_tags()
        key = 'Xmp.xmp.CreateDate'
        tag = self.metadata._get_xmp_tag(key)
        value = '2009-04-21T20:12:47+01:00'
        self.failIfEqual(self.metadata._image.tags['xmp'][key], value)
        self.metadata._set_xmp_tag_value(key, value)
        self.assertEqual(self.metadata._image.tags['xmp'][key], value)

    def test_delete_xmp_tag_inexistent(self):
        self.metadata.read()
        self._set_xmp_tags()
        key = 'Xmp.xmp.CreatorTool'
        self.failUnlessRaises(KeyError, self.metadata._delete_xmp_tag, key)

    def test_delete_xmp_tag_not_cached(self):
        self.metadata.read()
        self._set_xmp_tags()
        key = 'Xmp.dc.subject'
        self.assertEqual(self.metadata._tags['xmp'], {})
        self.assert_(self.metadata._image.tags['xmp'].has_key(key))
        self.metadata._delete_xmp_tag(key)
        self.assertEqual(self.metadata._tags['xmp'], {})
        self.failIf(self.metadata._image.tags['xmp'].has_key(key))

    def test_delete_xmp_tag_cached(self):
        self.metadata.read()
        self._set_xmp_tags()
        key = 'Xmp.dc.subject'
        self.assert_(self.metadata._image.tags['xmp'].has_key(key))
        tag = self.metadata._get_xmp_tag(key)
        self.assertEqual(self.metadata._tags['xmp'][key], tag)
        self.metadata._delete_xmp_tag(key)
        self.assertEqual(self.metadata._tags['xmp'], {})
        self.failIf(self.metadata._image.tags['xmp'].has_key(key))

    ###########################
    # Test dictionary interface
    ###########################

    def test_getitem(self):
        self.metadata.read()
        self._set_exif_tags()
        self._set_iptc_tags()
        self._set_xmp_tags()
        # Get existing tags
        key = 'Exif.Photo.ExifVersion'
        tag = self.metadata[key]
        self.assertEqual(type(tag), ExifTag)
        key = 'Iptc.Application2.Caption'
        tag = self.metadata[key]
        self.assertEqual(type(tag), IptcTag)
        key = 'Xmp.xmp.CreateDate'
        tag = self.metadata[key]
        self.assertEqual(type(tag), XmpTag)
        # Try to get nonexistent tags
        keys = ('Exif.Image.SamplesPerPixel', 'Iptc.Application2.FixtureId',
                'Xmp.xmp.Rating', 'Wrong.Noluck.Raise')
        for key in keys:
            self.failUnlessRaises(KeyError, self.metadata.__getitem__, key)

    def test_setitem(self):
        self.metadata.read()
        self._set_exif_tags()
        self._set_iptc_tags()
        self._set_xmp_tags()
        # Set new tags
        key = 'Exif.Photo.ExposureBiasValue'
        tag = ExifTag(key, 'ExposureBiasValue', 'Exposure Bias',
                      'The exposure bias. The units is the APEX value. ' \
                      'Ordinarily it is given in the range of -99.99 to 99.99.',
                      'SRational', '0/3', '0')
        self.metadata[key] = tag
        self.failUnless(key in self.metadata._tags['exif'])
        self.failUnlessEqual(self.metadata._tags['exif'][key], tag)
        key = 'Iptc.Application2.City'
        tag = IptcTag(key, 'City', 'City', 'Identifies city of object data ' \
                      'origin according to guidelines established by the ' \
                      'provider.', 'String', ['Barcelona'])
        self.metadata[key] = tag
        self.failUnless(key in self.metadata._tags['iptc'])
        self.failUnlessEqual(self.metadata._tags['iptc'][key], tag)
        key = 'Xmp.dc.description'
        tag = XmpTag(key, 'description', 'Description', 'A textual ' \
                     'description of the content of the resource. Multiple ' \
                     'values may be present for different languages.',
                     'Lang Alt', 'lang="x-default" Sunset picture.')
        self.metadata[key] = tag
        self.failUnless(key in self.metadata._tags['xmp'])
        self.failUnlessEqual(self.metadata._tags['xmp'][key], tag)
        # Replace existing tags
        key = 'Exif.Photo.ExifVersion'
        tag = ExifTag(key, 'ExifVersion', 'Exif Version', 'The version of ' \
                      'this standard supported. Nonexistence of this field is' \
                      ' taken to mean nonconformance to the standard.',
                      'Undefined', '48 50 50 48 ', '2.20')
        self.metadata[key] = tag
        self.failUnless(key in self.metadata._tags['exif'])
        self.failUnlessEqual(self.metadata._tags['exif'][key], tag)
        key = 'Iptc.Application2.Caption'
        tag = IptcTag(key, 'Caption', 'Caption', 'A textual description of ' \
                      'the object data.', 'String', ['Sunset on Barcelona.'])
        self.metadata[key] = tag
        self.failUnless(key in self.metadata._tags['iptc'])
        self.failUnlessEqual(self.metadata._tags['iptc'][key], tag)
        key = 'Xmp.dc.subject'
        tag = XmpTag(key, 'subject', 'Subject', 'An unordered array of ' \
                     'descriptive phrases or keywords that specify the topic ' \
                     'of the content of the resource.', 'bag Text',
                     'sunset, Barcelona, beautiful, beach')
        self.metadata[key] = tag
        self.failUnless(key in self.metadata._tags['xmp'])
        self.failUnlessEqual(self.metadata._tags['xmp'][key], tag)

    def test_delitem(self):
        self.metadata.read()
        self._set_exif_tags()
        self._set_iptc_tags()
        self._set_xmp_tags()
        # Delete existing tags
        key = 'Exif.Photo.ExifVersion'
        del self.metadata[key]
        self.failIf(key in self.metadata._tags['exif'])
        key = 'Iptc.Application2.Caption'
        del self.metadata[key]
        self.failIf(key in self.metadata._tags['iptc'])
        key = 'Xmp.xmp.CreateDate'
        del self.metadata[key]
        self.failIf(key in self.metadata._tags['xmp'])
        # Try to delete nonexistent tags
        keys = ('Exif.Image.SamplesPerPixel', 'Iptc.Application2.FixtureId',
                'Xmp.xmp.Rating', 'Wrong.Noluck.Raise')
        for key in keys:
            self.failUnlessRaises(KeyError, self.metadata.__delitem__, key)