Add clear() method on DownloadList

tests/test_dlist.py

@@ -208,6 +208,18 @@ class TestGetItems(unittest.TestCase):
         self.assertEqual(dlist.get_items(), [])
 
 
+class TestClear(unittest.TestCase):
+
+    """Test case for the DownloadList clear method."""
+
+    def test_clear(self):
+        dlist = DownloadList([mock.Mock() for _ in range(3)])
+
+        self.assertEqual(len(dlist), 3)
+        dlist.clear()
+        self.assertEqual(len(dlist), 0)
+
+
 class TestSynchronizeDecorator(unittest.TestCase):
 
     def test_synchronize(self):

youtube_dl_gui/downloadmanager.py

@@ -182,6 +182,12 @@ class DownloadList(object):
             self._items_list = [item.object_id for item in items]
             self._items_dict = {item.object_id: item for item in items}
 
+    @synchronized(_SYNC_LOCK)
+    def clear(self):
+        """Removes all the items from the list even the 'Active' ones."""
+        self._items_list = []
+        self._items_dict = {}
+
     @synchronized(_SYNC_LOCK)
     def insert(self, item):
         """Inserts the given item to the list. Does not check for duplicates. """