Added tests and ValueError for (un)sorted NdMappings

holoviews/core/ndmapping.py

@@ -109,6 +109,10 @@ def __init__(self, initial_items=None, **params):
         self._cached_categorical = any(d.values for d in self.kdims)
 
         if initial_items is None: initial_items = []
+        if type(initial_items) is dict and not sort:
+            raise ValueError('If sort=False the data must define a fixed '
+                             'ordering, please supply a list of items or '
+                             'an OrderedDict, not a regular dictionary.')
         if isinstance(initial_items, tuple):
             self._add_item(initial_items[0], initial_items[1])
         elif not self._check_items:

tests/testndmapping.py

@@ -88,6 +88,23 @@ def test_idxmapping_nested_update(self):
         nested_ndmap[1.5] = ndmap3
         self.assertEquals(list(nested_ndmap[1.5].values()), ['e', 'f'])
 
+    def test_idxmapping_unsorted(self):
+        data = [('B', 1), ('C', 2), ('A', 3)]
+        ndmap = MultiDimensionalMapping(data, sort=False)
+        self.assertEquals(ndmap.keys(), ['B', 'C', 'A'])
+
+    def test_idxmapping_unsorted_clone(self):
+        data = [('B', 1), ('C', 2), ('A', 3)]
+        ndmap = MultiDimensionalMapping(data, sort=False).clone()
+        self.assertEquals(ndmap.keys(), ['B', 'C', 'A'])
+
+    def test_idxmapping_groupby_unsorted(self):
+        data = [(('B', 2), 1), (('C', 2), 2), (('A', 1), 3)]
+        grouped = MultiDimensionalMapping(data, sort=False, kdims=['X', 'Y']).groupby('Y')
+        self.assertEquals(grouped.keys(), [1, 2])
+        self.assertEquals(grouped.values()[0].keys(), ['A'])
+        self.assertEquals(grouped.last.keys(), ['B', 'C'])
+
     def test_idxmapping_reindex(self):
         data = [((0, 0.5), 'a'), ((1, 0.5), 'b')]
         ndmap = MultiDimensionalMapping(data, kdims=[self.dim1, self.dim2])