test: add additional unit test for SPD and DIR

Author: adolfo-ab

pyproject.toml

@@ -17,6 +17,8 @@ dependencies = [
     "h5py>=3.13.0,<4",
     "scikit-learn",
     "aif360",
+    "hypothesis>=6.136.2",
+    "pytest>=8.4.1",
 ]
 
 [project.optional-dependencies]

src/core/metrics/fairness/group/group_statistical_parity_difference.py

@@ -4,18 +4,20 @@
 import numpy as np
 from sklearn.base import ClassifierMixin
 
+
 class GroupStatisticalParityDifference:
     """
     Calculate group statistical parity difference (SPD).
     """
+
     @staticmethod
     def calculate_model(
         samples: np.ndarray,
         model: ClassifierMixin,
         privilege_columns: List[int],
         privilege_values: List[int],
         favorable_output,
-        ) -> float:
+    ) -> float:
         """
         Calculate group statistical parity difference (SPD) for model outputs.
         :param samples a NumPy array of inputs to be used for testing fairness
@@ -37,13 +39,13 @@ def calculate(
         privileged,
         unprivileged,
         favorable_output,
-        ) -> float:
+    ) -> float:
         """
         Calculate statistical/demographic parity difference (SPD) when the labels are pre-calculated.
         :param priviledged numPy array with the privileged groups
         :param unpriviledged numPy array with the unpriviledged groups
         :param favorableOutput an output that is considered favorable / desirable
-        return SPD, between 0 and 1
+        return SPD, between -1 and 1
         """
         probability_privileged = np.sum(privileged[:, -1] == favorable_output) / len(privileged)
         probability_unprivileged = np.sum(unprivileged[:, -1] == favorable_output) / len(unprivileged)