mediagoblin/tests/test_exif.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import os
  18 try:
  19     from PIL import Image
  20 except ImportError:
  21     import Image
  22
  23 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  24     extract_exif, clean_exif, get_gps_data, get_useful
  25 from .resources import GOOD_JPG, EMPTY_JPG, BAD_JPG, GPS_JPG
  26 from mediagoblin.tools.testing import _activate_testing
  27
  28 _activate_testing()
  29
  30
  31 def assert_in(a, b):
  32     assert a in b, "%r not in %r" % (a, b)
  33
  34
  35 def test_exif_extraction():
  36     '''
  37     Test EXIF extraction from a good image
  38     '''
  39     result = extract_exif(GOOD_JPG)
  40     clean = clean_exif(result)
  41     useful = get_useful(clean)
  42     gps = get_gps_data(result)
  43
  44     # Do we have the result?
  45     assert len(result) == 56
  46
  47     # Do we have clean data?
  48     assert len(clean) == 53
  49
  50     # GPS data?
  51     assert gps == {}
  52
  53     # Do we have the "useful" tags?
  54     assert useful == {
  55         'EXIF Flash': {
  56             'field_type': 3,
  57             'printable': u'Flash did not fire',
  58             'field_offset': 380,
  59             'tag': 37385,
  60             'values': [0],
  61             'field_length': 2},
  62         'EXIF ExposureTime': {
  63             'field_type': 5,
  64             'printable': '1/125',
  65             'field_offset': 700,
  66             'tag': 33434,
  67             'values': [[1, 125]],
  68             'field_length': 8},
  69         'EXIF FocalLength': {
  70             'field_type': 5,
  71             'printable': '18',
  72             'field_offset': 780,
  73             'tag': 37386,
  74             'values': [[18, 1]],
  75             'field_length': 8},
  76         'Image Model': {
  77             'field_type': 2,
  78             'printable': 'NIKON D80',
  79             'field_offset': 152,
  80             'tag': 272,
  81             'values': 'NIKON D80',
  82             'field_length': 10},
  83         'Image Make': {
  84             'field_type': 2,
  85             'printable': 'NIKON CORPORATION',
  86             'field_offset': 134,
  87             'tag': 271,
  88             'values': 'NIKON CORPORATION',
  89             'field_length': 18},
  90         'EXIF ExposureMode': {
  91             'field_type': 3,
  92             'printable': 'Manual Exposure',
  93             'field_offset': 584,
  94             'tag': 41986,
  95             'values': [1],
  96             'field_length': 2},
  97         'EXIF ISOSpeedRatings': {
  98             'field_type': 3,
  99             'printable': '100',
 100             'field_offset': 260,
 101             'tag': 34855,
 102             'values': [100],
 103             'field_length': 2},
 104         'EXIF FNumber': {
 105             'field_type': 5,
 106             'printable': '10',
 107             'field_offset': 708,
 108             'tag': 33437,
 109             'values': [[10, 1]],
 110             'field_length': 8}}
 111
 112
 113 def test_exif_image_orientation():
 114     '''
 115     Test image reorientation based on EXIF data
 116     '''
 117     result = extract_exif(GOOD_JPG)
 118
 119     image = exif_fix_image_orientation(
 120         Image.open(GOOD_JPG),
 121         result)
 122
 123     # Are the dimensions correct?
 124     assert image.size == (428, 640)
 125
 126     # If this pixel looks right, the rest of the image probably will too.
 127     assert_in(image.getdata()[10000],
 128               ((41, 28, 11), (43, 27, 11))
 129               )
 130
 131
 132 def test_exif_no_exif():
 133     '''
 134     Test an image without exif
 135     '''
 136     result = extract_exif(EMPTY_JPG)
 137     clean = clean_exif(result)
 138     useful = get_useful(clean)
 139     gps = get_gps_data(result)
 140
 141     assert result == {}
 142     assert clean == {}
 143     assert gps == {}
 144     assert useful == {}
 145
 146
 147 def test_exif_bad_image():
 148     '''
 149     Test EXIF extraction from a faithful, but bad image
 150     '''
 151     result = extract_exif(BAD_JPG)
 152     clean = clean_exif(result)
 153     useful = get_useful(clean)
 154     gps = get_gps_data(result)
 155
 156     assert result == {}
 157     assert clean == {}
 158     assert gps == {}
 159     assert useful == {}
 160
 161
 162 def test_exif_gps_data():
 163     '''
 164     Test extractiion of GPS data
 165     '''
 166     result = extract_exif(GPS_JPG)
 167     gps = get_gps_data(result)
 168
 169     assert gps == {
 170         'latitude': 59.336666666666666,
 171         'direction': 25.674046740467404,
 172         'altitude': 37.64365671641791,
 173         'longitude': 18.016166666666667}