Fix downloading from "marker" item

The documentation of "swift download" hints that "marker" option
is supported, but in reality we forgot to patch it through, so
all downloads were always done with the default, empty marker.

Closes-Bug: #1565393
Change-Id: I38bd29d2baa9188b61397dec75ce1d864041653c

swiftclient/service.py

@@ -883,7 +883,7 @@ class SwiftService(object):
 
     @staticmethod
     def _list_container_job(conn, container, options, result_queue):
-        marker = ''
+        marker = options.get('marker', '')
         error = None
         try:
             while True:

swiftclient/shell.py

@@ -203,7 +203,7 @@ def st_delete(parser, args, output_manager):
             output_manager.error(err.value)
 
 
-st_download_options = '''[--all] [--marker] [--prefix <prefix>]
+st_download_options = '''[--all] [--marker <marker>] [--prefix <prefix>]
                       [--output <out_file>] [--output-dir <out_directory>]
                       [--object-threads <threads>]
                       [--container-threads <threads>] [--no-download]
@@ -225,7 +225,7 @@ Positional arguments:
 Optional arguments:
   -a, --all             Indicates that you really want to download
                         everything in the account.
-  -m, --marker          Marker to use when starting a container or account
+  -m, --marker <marker> Marker to use when starting a container or account
                         download.
   -p, --prefix <prefix> Only download items beginning with <prefix>
   -r, --remove-prefix   An optional flag for --prefix <prefix>, use this

tests/unit/test_service.py

@@ -687,6 +687,41 @@ class TestServiceList(_TestServiceBase):
         self.assertEqual(expected_r_long, self._get_queue(mock_q))
         self.assertIsNone(self._get_queue(mock_q))
 
+    def test_list_container_marker(self):
+        mock_q = Queue()
+        mock_conn = self._get_mock_connection()
+
+        get_container_returns = [
+            (None, [{'name': 'b'}, {'name': 'c'}]),
+            (None, [])
+        ]
+        mock_get_cont = Mock(side_effect=get_container_returns)
+        mock_conn.get_container = mock_get_cont
+
+        expected_r = self._get_expected({
+            'action': 'list_container_part',
+            'container': 'test_c',
+            'success': True,
+            'listing': [{'name': 'b'}, {'name': 'c'}],
+            'marker': 'b'
+        })
+
+        _opts = self.opts.copy()
+        _opts['marker'] = 'b'
+        SwiftService._list_container_job(mock_conn, 'test_c', _opts, mock_q)
+
+        # This does not test if the marker is propagated, because we always
+        # get the final call to the get_container with the final item 'c',
+        # even if marker wasn't set. This test just makes sure the whole
+        # stack works in a sane way.
+        mock_kw = mock_get_cont.call_args[1]
+        self.assertEqual(mock_kw['marker'], 'c')
+
+        # This tests that the lower levels get the marker delivered.
+        self.assertEqual(expected_r, self._get_queue(mock_q))
+
+        self.assertIsNone(self._get_queue(mock_q))
+
     def test_list_container_exception(self):
         mock_q = Queue()
         mock_conn = self._get_mock_connection()