Replace Metadata.get_single_front_image() with ImageList.get_front_image()

- it makes much more sense, Metadata.images is an ImageList
- minimal changes required
- add tests for it

picard/file.py

@@ -444,7 +444,7 @@ class File(QtCore.QObject, Item):
         counters = defaultdict(lambda: 0)
         images = []
         if config.setting["caa_save_single_front_image"]:
-            images = metadata.get_single_front_image()
+            images = [metadata.images.get_front_image()]
         if not images:
             images = metadata.images
         for image in images:

picard/metadata.py

@@ -103,19 +103,11 @@ class Metadata(MutableMapping):
             return ()
         images = [img for img in self.images if img.can_be_saved_to_tags]
         if config.setting["embed_only_one_front_image"]:
-            front_image = self.get_single_front_image(images)
+            front_image = self.images.get_front_image()
             if front_image:
-                return front_image
+                return [front_image]
         return images
 
-    def get_single_front_image(self, images=None):
-        if not images:
-            images = self.images
-        for img in images:
-            if img.is_front_image():
-                return [img]
-        return []
-
     def remove_image(self, index):
         self.images.pop(index)
 

picard/util/imagelist.py

@@ -34,6 +34,12 @@ class ImageList(list):
         except TypeError:
             return result
 
+    def get_front_image(self):
+        for img in self:
+            if img.is_front_image():
+                return img
+        return None
+
 
 class ImageListState:
     def __init__(self):

test/test_imagelist.py

@@ -264,3 +264,8 @@ class ImageListTest(PicardTestCase):
 
         self.assertTrue(list1 == list2)
         self.assertFalse(list1 == list3)
+
+    def test_get_front_image(self):
+        self.imagelist.append(self.images['a'])
+        self.imagelist.append(self.images['b'])
+        self.assertEqual(self.imagelist.get_front_image(), self.images['b'])