add test for new style groups

This test currently fails.

tests/make_new_style_groups_file.py

@@ -0,0 +1,9 @@
+#! /usr/bin/env python
+""" Create a HDF5 file with new-style groups. """
+import h5py
+import numpy as np
+
+
+f = h5py.File('new_style_groups.hdf5', 'w', track_order=True)
+for i in range(9):
+    f.create_group('group' + str(i))

tests/test_new_style_groups.py

@@ -0,0 +1,23 @@
+""" Test new style groups in pyfive. """
+import os
+
+import pyfive
+
+DIRNAME = os.path.dirname(__file__)
+NEW_STYLE_GROUPS_HDF5_FILE = os.path.join(DIRNAME, 'new_style_groups.hdf5')
+
+
+def test_groups():
+
+    with pyfive.File(NEW_STYLE_GROUPS_HDF5_FILE) as hfile:
+
+        assert len(hfile) == 9
+        grp0 = hfile['group0']
+        grp1 = hfile['group1']
+        grp2 = hfile['group2']
+        grp3 = hfile['group3']
+        grp4 = hfile['group4']
+        grp5 = hfile['group5']
+        grp6 = hfile['group6']
+        grp7 = hfile['group7']
+        grp8 = hfile['group8']