def test_check_for_valid_data_length_returns_error_when_data_length_to_large_for_image(self):
     image_data = Image.open("tests/test_resources/small_rgba.png").getdata()
     data_to_hide = Image.open("tests/test_resources/rgb_image.png").getdata()
     with self.assertRaisesRegexp(ValueError, "The data provided is too large to fit in the image"):
         stegano.check_for_valid_data_length(image_data, data_to_hide)
 def test_check_for_valid_data_length_returns_error_when_data_length_is_zero(self):
     image_data = Image.open("tests/test_resources/small_rgba.png").getdata()
     data_to_hide = ""
     with self.assertRaisesRegexp(ValueError, "No data was provided to hide"):
         stegano.check_for_valid_data_length(image_data, data_to_hide)
 def test_check_for_valid_data_length_returns_data_length_when_arguments_are_valid(self):
     image_data = Image.open("tests/test_resources/rgb_image.png").getdata()
     data_to_hide = open("tests/test_resources/hide_me.txt", "r").read()
     self.assertEqual(stegano.check_for_valid_data_length(image_data, data_to_hide), 24)