update topline hang for empty iterables

README.rst

@@ -6,6 +6,9 @@ Iteround: Sum-safe Rounding for Iterables
 .. image:: https://img.shields.io/pypi/v/iteround.svg
     :target: https://pypi.org/project/iteround/
 
+.. image:: https://img.shields.io/conda/vn/conda-forge/iteround.svg
+    :target: https://anaconda.org/conda-forge/iteround
+
 Iteround is an organic (standard library) sum-safe rounding library for Python
 iterables (lists, tuples, dicts).
 

iteround/core.py

@@ -78,7 +78,7 @@ def saferound(iterable, places, strategy=DIFFERENCE, rounder=round, topline=None
     local_sum = _sumnum(local, places, rounder)
 
     # adjust values to adhere to original sum
-    while local_sum != orig_sum:
+    while local and local_sum != orig_sum:
         diff = rounder(orig_sum - local_sum, places)
         if diff < 0.:
             increment = -1 * _mininc(places)

tests/test_saferound.py

@@ -91,6 +91,12 @@ def test_topline_sum(self):
         self.assertEqual(sum(iteround.saferound(self.in_list, 0, topline=29)), 29)
         self.assertEqual(sum(iteround.saferound(self.in_list, 0, topline=30)), 30)
 
+    def test_empty_returns_empty(self):
+        out = []
+        topline = 1
+        actual_out = iteround.saferound([], 0, topline=topline)
+        self.assertListEqual(actual_out, out)
+
 
 if __name__ == '__main__':
     unittest.main()