Add unit tests for image comparison

flatisfy/filters/cache.py

@@ -13,17 +13,15 @@ class MemoryCache(object):
     """
     A cache in memory.
     """
-    def __init__(self, on_miss):
-        """
-        Constructor
 
-        :param on_miss: Function to call to retrieve item when not already
-        cached.
-        """
+    @staticmethod
+    def on_miss(key):
+        raise NotImplementedError
+
+    def __init__(self):
         self.hits = 0
         self.misses = 0
         self.map = {}
-        self.on_miss = on_miss
 
     def get(self, key):
         """
@@ -77,11 +75,8 @@ class ImageCache(MemoryCache):
     A cache for images, stored in memory.
     """
     @staticmethod
-    def retrieve_photo(url):
+    def on_miss(url):
         """
         Helper to actually retrieve photos if not already cached.
         """
         return requests.get(url)
-
-    def __init__(self):
-        super(ImageCache, self).__init__(on_miss=ImageCache.retrieve_photo)

flatisfy/filters/duplicates.py

@@ -67,31 +67,51 @@ def get_or_compute_photo_hash(photo, photo_cache):
         return photo["hash"]
 
 
-def find_number_common_photos(flat1_photos, flat2_photos, photo_cache):
+def compare_photos(photo1, photo2, photo_cache, hash_threshold=10):
+    """
+    Compares two photos with average hash method.
+
+    :param photo1: First photo url.
+    :param photo2: Second photo url.
+    :param photo_cache: An instance of ``ImageCache`` to use to cache images.
+    :param hash_thresold: The hash threshold between two images. Usually two
+    different photos have a hash difference of 30.
+    :return: ``True`` if the photos are identical, else ``False``.
+    """
+    try:
+        hash1 = get_or_compute_photo_hash(photo1, photo_cache)
+        hash2 = get_or_compute_photo_hash(photo2, photo_cache)
+
+        return hash1 - hash2 < hash_threshold
+    except (IOError, requests.exceptions.RequestException):
+        return False
+
+
+def find_number_common_photos(
+    flat1_photos,
+    flat2_photos,
+    photo_cache,
+    hash_threshold=10
+):
     """
     Compute the number of common photos between the two lists of photos for the
     flats.
 
-    Fetch the photos and compare them with dHash method.
+    Fetch the photos and compare them with average hash method.
 
     :param flat1_photos: First list of flat photos. Each photo should be a
         ``dict`` with (at least) a ``url`` key.
-    :param flat2_photos: First list of flat photos. Each photo should be a
+    :param flat2_photos: Second list of flat photos. Each photo should be a
         ``dict`` with (at least) a ``url`` key.
     :param photo_cache: An instance of ``ImageCache`` to use to cache images.
+    :param hash_thresold: The hash threshold between two images.
     :return: The found number of common photos.
     """
     n_common_photos = 0
 
     for photo1, photo2 in itertools.product(flat1_photos, flat2_photos):
-        try:
-            hash1 = get_or_compute_photo_hash(photo1, photo_cache)
-            hash2 = get_or_compute_photo_hash(photo2, photo_cache)
-
-            if hash1 - hash2 == 0:
-                n_common_photos += 1
-        except (IOError, requests.exceptions.RequestException):
-            pass
+        if compare_photos(photo1, photo2, photo_cache, hash_threshold):
+            n_common_photos += 1
 
     return n_common_photos
 
@@ -182,7 +202,7 @@ def detect(flats_list, key="id", merge=True, should_intersect=False):
     return unique_flats_list, duplicate_flats
 
 
-def get_duplicate_score(flat1, flat2, photo_cache):
+def get_duplicate_score(flat1, flat2, photo_cache, hash_threshold=10):
     """
     Compute the duplicate score between two flats. The higher the score, the
     more likely the two flats to be duplicates.
@@ -190,6 +210,7 @@ def get_duplicate_score(flat1, flat2, photo_cache):
     :param flat1: First flat dict.
     :param flat2: Second flat dict.
     :param photo_cache: An instance of ``ImageCache`` to use to cache images.
+    :param hash_thresold: The hash threshold between two images.
     :return: The duplicate score as ``int``.
     """
     n_common_items = 0
@@ -314,7 +335,12 @@ def deep_detect(flats_list, config):
             if flat2["id"] in matching_flats[flat1["id"]]:
                 continue
 
-            n_common_items = get_duplicate_score(flat1, flat2, photo_cache)
+            n_common_items = get_duplicate_score(
+                flat1,
+                flat2,
+                photo_cache,
+                config["duplicate_image_hash_threshold"]
+            )
 
             # Minimal score to consider they are duplicates
             if n_common_items >= config["duplicate_threshold"]:

flatisfy/tests.py

@@ -9,6 +9,8 @@ import os
 import random
 import sys
 import unittest
+import requests
+import requests_mock
 
 from flatisfy import tools
 from flatisfy.filters import duplicates
@@ -19,6 +21,22 @@ LOGGER = logging.getLogger(__name__)
 TESTS_DATA_DIR = os.path.dirname(os.path.realpath(__file__)) + "/test_files/"
 
 
+class LocalImageCache(ImageCache):
+    """
+    A local cache for images, stored in memory.
+    """
+    @staticmethod
+    def on_miss(path):
+        """
+        Helper to actually retrieve photos if not already cached.
+        """
+        url = "mock://flatisfy" + path
+        with requests_mock.Mocker() as mock:
+            with open(path, "rb") as fh:
+                mock.get(url, content=fh.read())
+                return requests.get(url)
+
+
 class TestTexts(unittest.TestCase):
     """
     Checks string normalizations.
@@ -118,6 +136,68 @@ class TestPhoneNumbers(unittest.TestCase):
         )
 
 
+class TestPhotos(unittest.TestCase):
+    IMAGE_CACHE = LocalImageCache()  # pylint: disable=invalid-name
+
+    def test_same_photo_twice(self):
+        """
+        Compares a photo against itself.
+        """
+        photo = {
+            "url": TESTS_DATA_DIR + "127028739@seloger.jpg"
+        }
+
+        self.assertTrue(duplicates.compare_photos(
+            photo,
+            photo,
+            TestPhotos.IMAGE_CACHE
+        ))
+
+    def test_different_photos(self):
+        """
+        Compares two different photos.
+        """
+        self.assertFalse(duplicates.compare_photos(
+            {"url": TESTS_DATA_DIR + "127028739@seloger.jpg"},
+            {"url": TESTS_DATA_DIR + "127028739-2@seloger.jpg"},
+            TestPhotos.IMAGE_CACHE
+        ))
+
+        self.assertFalse(duplicates.compare_photos(
+            {"url": TESTS_DATA_DIR + "127028739-2@seloger.jpg"},
+            {"url": TESTS_DATA_DIR + "127028739-3@seloger.jpg"},
+            TestPhotos.IMAGE_CACHE
+        ))
+
+    def test_matching_photos(self):
+        """
+        Compares two matching photos with different size and source.
+        """
+        self.assertTrue(duplicates.compare_photos(
+            {"url": TESTS_DATA_DIR + "127028739@seloger.jpg"},
+            {"url": TESTS_DATA_DIR + "14428129@explorimmo.jpg"},
+            TestPhotos.IMAGE_CACHE
+        ))
+
+        self.assertTrue(duplicates.compare_photos(
+            {"url": TESTS_DATA_DIR + "127028739-2@seloger.jpg"},
+            {"url": TESTS_DATA_DIR + "14428129-2@explorimmo.jpg"},
+            TestPhotos.IMAGE_CACHE
+        ))
+
+        self.assertTrue(duplicates.compare_photos(
+            {"url": TESTS_DATA_DIR + "127028739-3@seloger.jpg"},
+            {"url": TESTS_DATA_DIR + "14428129-3@explorimmo.jpg"},
+            TestPhotos.IMAGE_CACHE
+        ))
+
+        self.assertTrue(duplicates.compare_photos(
+            {"url": TESTS_DATA_DIR + "127028739@seloger.jpg"},
+            {"url": TESTS_DATA_DIR + "127028739-watermark@seloger.jpg"},
+            TestPhotos.IMAGE_CACHE
+        ))
+
+
 class TestDuplicates(unittest.TestCase):
     """
     Checks duplicates detection.
@@ -286,5 +366,9 @@ def run():
         suite = unittest.TestLoader().loadTestsFromTestCase(TestDuplicates)
         result = unittest.TextTestRunner(verbosity=2).run(suite)
         assert result.wasSuccessful()
+
+        suite = unittest.TestLoader().loadTestsFromTestCase(TestPhotos)
+        result = unittest.TextTestRunner(verbosity=2).run(suite)
+        assert result.wasSuccessful()
     except AssertionError:
         sys.exit(1)

requirements.txt

@@ -10,6 +10,7 @@ future
 imagehash
 pillow
 requests
+requests_mock
 sqlalchemy
 titlecase
 unidecode