def test_can_encrypt_method(self):
# 32 pixels are required for end message code
# 4 x 4 x 3 = 48; (48 - 32) / 4 = 4 -> 4 characters possible
img_small = np.zeros((4, 4, 3), np.uint8)
# 5 x 5 x 3 = 75; (75 - 32) / 4 ~= 10+ -> 10 characters possible
img_ok = np.zeros((5, 5, 3), np.uint8)
# 6x6 - minimum image size for encryption
img_one_channel = np.zeros((6, 6, 1), np.uint8)
text_small = "test"
text = "10letters!"
text_long = "Too long string"
self.assertTrue(Encrypter.can_encrypt(img_small, text_small))
self.assertFalse(Encrypter.can_encrypt(img_small, text))
self.assertTrue(Encrypter.can_encrypt(img_ok, text))
self.assertFalse(Encrypter.can_encrypt(img_ok, text_long))
self.assertFalse(Encrypter.can_encrypt(img_one_channel, text))
self.assertTrue(Encrypter.can_encrypt(img_one_channel, "1"))
