Added 'tags' argument to snapshot command (#157)

Added functionality to specify restic's `--tag` argument when using the
`snapshots()` command. Added associated unit test.

docs/index.md

@@ -475,6 +475,7 @@ Retrieve a list of snapshots in the repo
 
 - `snapshot_id`: ID of the snapshot which should be listed
 - `group_by`: String for grouping snapshots by host, paths, tags
+- `tags`: List of snapshot tags
 
 ### Returns
 

restic/internal/snapshots.py

@@ -3,7 +3,7 @@
 from restic.internal import command_executor
 
 
-def run(restic_base_command, snapshot_id=None, group_by=None):
+def run(restic_base_command, snapshot_id=None, group_by=None, tags=None):
     cmd = restic_base_command + ['snapshots']
 
     if snapshot_id:
@@ -12,4 +12,7 @@ def run(restic_base_command, snapshot_id=None, group_by=None):
     if group_by:
         cmd.extend(['--group-by', group_by])
 
+    if tags:
+        cmd.extend(['--tag', ','.join(tags)])
+
     return json.loads(command_executor.execute(cmd))

restic/internal/snapshots_test.py

@@ -36,6 +36,15 @@ def test_snapshots_id(self, mock_execute):
         mock_execute.assert_called_with(
             ['restic', '--json', 'snapshots', 'latest'])
 
+    @mock.patch.object(snapshots.command_executor, 'execute')
+    def test_snapshots_tags(self, mock_execute):
+        mock_execute.return_value = '[]'
+
+        self.assertEqual([], restic.snapshots(tags=['test', 'test2']))
+
+        mock_execute.assert_called_with(
+            ['restic', '--json', 'snapshots', '--tag', 'test,test2'])
+
     @mock.patch.object(snapshots.command_executor, 'execute')
     def test_snapshots_parses_result_json(self, mock_execute):
         mock_execute.return_value = """