TST: Panel ctor and from_dict should respect ordering when given OrderedDict GH3303

Author: y-p

pandas/core/panel.py

@@ -13,7 +13,7 @@
 from pandas.core.index import (Index, MultiIndex, _ensure_index,
                                _get_combined_index)
 from pandas.core.indexing import _maybe_droplevels, _is_list_like
-from pandas.core.internals import (BlockManager, 
+from pandas.core.internals import (BlockManager,
                                    create_block_manager_from_arrays,
                                    create_block_manager_from_blocks)
 from pandas.core.series import Series

pandas/tests/test_panel.py

@@ -19,7 +19,9 @@
                                  assert_frame_equal,
                                  assert_series_equal,
                                  assert_almost_equal,
-                                 ensure_clean)
+                                 ensure_clean,
+                                 makeCustomDataframe as mkdf
+    )
 import pandas.core.panel as panelm
 import pandas.util.testing as tm
 
@@ -904,6 +906,16 @@ def test_constructor_dict_mixed(self):
         data['ItemB'] = self.panel['ItemB'].values[:, :-1]
         self.assertRaises(Exception, Panel, data)
 
+    def test_ctor_orderedDict(self):
+        from pandas.util.compat import OrderedDict
+        keys = list(set(np.random.randint(0,5000,100)))[:50] # unique random int  keys
+        d = OrderedDict([(k,mkdf(10,5)) for k in keys])
+        p = Panel(d)
+        self.assertTrue(list(p.items) == keys)
+
+        p = Panel.from_dict(d)
+        self.assertTrue(list(p.items) == keys)
+
     def test_constructor_resize(self):
         data = self.panel._data
         items = self.panel.items[:-1]