Gini tests

Author: Simon-Rey

pabutools/utils.py

@@ -98,6 +98,7 @@ def gini_coefficient(values: Iterable[Numeric]) -> Numeric:
         return 0
     sorted_values: list[Numeric] = sorted(values)
     total_cum_sum: Numeric = 0
+    # Slightly different from Wikipedia because we start at 0
     for i, v in enumerate(sorted_values):
         total_cum_sum += v * (num_values - i)
     return frac(num_values + 1 - frac(2 * total_cum_sum, sum(values)), num_values)

tests/test_analysis.py

@@ -32,7 +32,8 @@ class TestAnalysis(TestCase):
 
     def test_gini(self):
         self.assertEqual(gini_coefficient([100 for _ in range(100)]), 0)
-        self.assertEqual(gini_coefficient([0, 0, 0, 0, 0, 0, 0, 0, 0, 1]), 1)
+        self.assertEqual(gini_coefficient([0, 0, 0, 100, 100, 100]), frac(1, 2))
+        self.assertEqual(gini_coefficient([1] * 75 + [9] * 25), frac(1, 2))
 
     def test_satisfaction_properties(self):
         projects = [Project(str(i), 10 + i) for i in range(10)]