Allow passing directory path in FolderData constructor (#3359)

This will initialize the node and copy over the tree pointed to by the
`tree` keyword argument into the node's repository.

aiida/backends/tests/__init__.py

@@ -118,6 +118,7 @@
         'orm.comments': ['aiida.backends.tests.orm.test_comments'],
         'orm.computers': ['aiida.backends.tests.orm.test_computers'],
         'orm.data.dict': ['aiida.backends.tests.orm.data.test_dict'],
+        'orm.data.folder': ['aiida.backends.tests.orm.data.test_folder'],
         'orm.data.kpoints': ['aiida.backends.tests.orm.data.test_kpoints'],
         'orm.data.orbital': ['aiida.backends.tests.orm.data.test_orbital'],
         'orm.data.remote': ['aiida.backends.tests.orm.data.test_remote'],

aiida/backends/tests/orm/data/test_folder.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+###########################################################################
+# Copyright (c), The AiiDA team. All rights reserved.                     #
+# This file is part of the AiiDA code.                                    #
+#                                                                         #
+# The code is hosted on GitHub at https://github.com/aiidateam/aiida-core #
+# For further information on the license, see the LICENSE.txt file        #
+# For further information please visit http://www.aiida.net               #
+###########################################################################
+"""Tests for the `FolderData` class."""
+from __future__ import division
+from __future__ import print_function
+from __future__ import absolute_import
+
+import io
+import os
+import shutil
+import tempfile
+
+from aiida.backends.testbase import AiidaTestCase
+from aiida.orm import FolderData
+
+
+class TestFolderData(AiidaTestCase):
+    """Test for the `FolderData` class."""
+
+    @classmethod
+    def setUpClass(cls, *args, **kwargs):
+        super(TestFolderData, cls).setUpClass(*args, **kwargs)
+        cls.tempdir = tempfile.mkdtemp()
+        cls.tree = {
+            'a.txt': u'Content of file A\nWith some newlines',
+            'b.txt': u'Content of file B without newline',
+        }
+
+        for filename, content in cls.tree.items():
+            with io.open(os.path.join(cls.tempdir, filename), 'w', encoding='utf8') as handle:
+                handle.write(content)
+
+    @classmethod
+    def tearDownClass(cls, *args, **kwargs):
+        shutil.rmtree(cls.tempdir)
+
+    def test_constructor_tree(self):
+        """Test the `tree` constructor keyword."""
+        node = FolderData(tree=self.tempdir)
+        self.assertEqual(sorted(node.list_object_names()), sorted(self.tree.keys()))

aiida/orm/nodes/data/folder.py

@@ -19,3 +19,25 @@
 
 class FolderData(Data):
     """`Data` sub class to represent a folder on a file system."""
+
+    def __init__(self, **kwargs):
+        """Construct a new `FolderData` to which any files and folders can be added.
+
+        Use the `tree` keyword to simply wrap a directory:
+
+            folder = FolderData(tree='/absolute/path/to/directory')
+
+        Alternatively, one can construct the node first and then use the various repository methods to add objects:
+
+            folder = FolderData()
+            folder.put_object_from_tree('/absolute/path/to/directory')
+            folder.put_object_from_filepath('/absolute/path/to/file.txt')
+            folder.put_object_from_filelike(filelike_object)
+
+        :param tree: absolute path to a folder to wrap
+        :type tree: str
+        """
+        tree = kwargs.pop('tree', None)
+        super(FolderData, self).__init__(**kwargs)
+        if tree:
+            self.put_object_from_tree(tree)