test.py

from __future__ import print_function
from PIL import Image
import imagehash

filename = 'testfile.jpg'

def retrieve_example():
	import os
	if not os.path.exists(filename):
		url = 'http://lh5.googleusercontent.com/-0iu4m4njVmQ/S3YH3wwXuPI/AAAAAAAABeU/i8jX5uKGCFo/s800/Alyson_Hannigan_200512.jpg'
		import urllib2
		response = urllib2.urlopen(url)
		open(filename, 'w').write(response.read())
	return Image.open(filename)

def run_hash_algorithm(algo):
	img = retrieve_example()
	hash = algo(img)
	print(hash)
	print("rotate slightly")
	imgrot = img.rotate(-1)
	otherhash = algo(imgrot)
	print(otherhash)
	print(hash == otherhash)
	assert hash - otherhash <= 8, ('slightly rotated image should have similar hash', hash, otherhash)
	#assert hash == otherhash, ('slightly rotated image should have same hash', hash, otherhash)
	
	print("rotate 90 degrees")
	imgrot = img.rotate(-90)
	otherhash = algo(imgrot)
	print(otherhash)
	print(hash == otherhash)
	assert hash != otherhash, ('rotated image should have different hash', hash, otherhash)
	assert hash - otherhash > 10, ('rotated image should have different hash', hash, otherhash)

def test_average_hash():
	run_hash_algorithm(imagehash.average_hash)

def test_dhash():
	run_hash_algorithm(imagehash.dhash)

def test_phash():
	run_hash_algorithm(imagehash.phash)


def test_average_hash_length():
	for hash_size in [8, 20]:
		print('checking if hash_size=%d is respected' % hash_size)
		hash = imagehash.average_hash(retrieve_example(), hash_size=hash_size)
		assert hash.hash.size == hash_size**2, hash.hash.shape

def test_dhash_length():
	for hash_size in [8, 20]:
		print('checking if hash_size=%d is respected' % hash_size)
		hash = imagehash.dhash(retrieve_example(), hash_size=hash_size)
		assert hash.hash.size == hash_size**2, hash.hash.shape

def test_phash_length():
	for hash_size in [8, 20]:
		print('checking if hash_size=%d is respected' % hash_size)
		hash = imagehash.phash(retrieve_example(), hash_size=hash_size)
		assert hash.hash.size == hash_size**2, hash.hash.shape

def test_stored_hashes():
	img = retrieve_example()
	hash = imagehash.average_hash(img)
	stored_hex = str(hash)
	print('checking if stringified hash is the same')
	otherhash = imagehash.hex_to_hash(stored_hex)
	print(otherhash)
	print(hash == otherhash)
	assert hash == otherhash
	assert hash - otherhash == 0