Pillow/Tests/test_file_ppm.py

from helper import unittest, PillowTestCase

from PIL import Image

# sample ppm stream
test_file = "Tests/images/hopper.ppm"


class TestFilePpm(PillowTestCase):

    def test_sanity(self):
        im = Image.open(test_file)
        im.load()
        self.assertEqual(im.mode, "RGB")
        self.assertEqual(im.size, (128, 128))
        self.assertEqual(im.format, "PPM")

    def test_16bit_pgm(self):
        im = Image.open('Tests/images/16_bit_binary.pgm')
        im.load()
        self.assertEqual(im.mode, 'I')
        self.assertEqual(im.size, (20, 100))

        tgt = Image.open('Tests/images/16_bit_binary_pgm.png')
        self.assert_image_equal(im, tgt)

    def test_16bit_pgm_write(self):
        im = Image.open('Tests/images/16_bit_binary.pgm')
        im.load()

        f = self.tempfile('temp.pgm')
        im.save(f, 'PPM')

        reloaded = Image.open(f)
        self.assert_image_equal(im, reloaded)

    def test_truncated_file(self):
        path = self.tempfile('temp.pgm')
        f = open(path, 'w')
        f.write('P6')
        f.close()

        self.assertRaises(ValueError, lambda: Image.open(path))


    def test_neg_ppm(self):
        # Storage.c accepted negative values for xsize, ysize.  the
        # internal open_ppm function didn't check for sanity but it
        # has been removed. The default opener doesn't accept negative
        # sizes. 
        
        with self.assertRaises(IOError):
            Image.open('Tests/images/negative_size.ppm')


if __name__ == '__main__':
    unittest.main()