Add epsilon when summing floats

Fix #3

Author: mwouts

easyplotly/internals.py

@@ -3,6 +3,12 @@
 import pandas as pd
 import numpy as np
 
+"""When computing the sum of weights, we had an epsilon to make sure that the JS code
+will see a total larger than the sum. See #3. Note that the example reported at #3 is
+fixed already with EPS=1e-16. But, since (0.1+0.2-0.3)*10=5.5e-16, we prefer to take
+a larger value here."""
+EPS = 1e-15
+
 
 def tree_like_structure_to_dict(values):
     """Transform a series, a dict, or a collection of such objects, into a dictionary index by tuples"""
@@ -51,7 +57,12 @@ def sunburst_or_treemap(values, root_label=None, branchvalues='total', **kwargs)
 
                 if branchvalues == 'total' and not np.isnan(value):
                     # Sum the descendent weights onto the parents (skip nans)
-                    tree[parent] += value
+                    if isinstance(value, int):
+                        tree[parent] += value
+                    else:
+                        # Make sure that the parent is going to be bigger
+                        # than the sum of values, even if we change the summation order (#3)
+                        tree[parent] += value * (1 + depth * EPS)
 
     def ends_with_none_or_nan(key):
         if not key:

requirements-dev.txt

@@ -6,6 +6,7 @@ jupytext
 nbconvert
 jupyter_client
 ipykernel
+mock
 
 # Examples
 world_bank_data

tests/test_sunburst.py

@@ -1,5 +1,10 @@
 import sys
 import pytest
+
+try:
+    import unittest.mock as mock
+except ImportError:
+    import mock
 import pandas as pd
 import plotly.graph_objects as go
 from easyplotly import Sunburst
@@ -93,3 +98,16 @@ def test_sunburst_index_none_is_removed():
 def test_negative_raise_error():
     with pytest.raises(ValueError, match='Negative'):
         Sunburst({('A', 'a'): -5})
+
+
+def test_parent_value_strictly_larger():
+    with mock.patch('easyplotly.internals.EPS', 0.01):
+        sunburst_input = {('A', 'a', '1', 'i'): 1.0}
+        sunburst_expected = go.Sunburst(
+            ids=['/A/a/1/i', '/A/a/1', '/A/a', '/A'],
+            labels=['i', '1', 'a', 'A'],
+            parents=['/A/a/1', '/A/a', '/A', None],
+            values=[1., 1.01, 1.02, 1.03],
+            branchvalues='total'
+        )
+        assert Sunburst(sunburst_input) == sunburst_expected