Objective: Add tests

tests/components/test_objective.py

@@ -8,11 +8,12 @@ from unittest.mock import Mock
 import numpy as np
 from numpy.testing import assert_array_equal
 
+from miplearn import GurobiPyomoSolver, LearningSolver
 from miplearn.instance import Instance
 from miplearn.classifiers import Regressor
 from miplearn.components.objective import ObjectiveValueComponent
 from miplearn.types import TrainingSample, Features
-from tests.fixtures.knapsack import get_test_pyomo_instances
+from tests.fixtures.knapsack import get_test_pyomo_instances, get_knapsack_instance
 
 
 def test_x_y_predict() -> None:
@@ -151,3 +152,13 @@ def test_xy_sample_without_lp() -> None:
     x_actual, y_actual = xy
     assert x_actual == x_expected
     assert y_actual == y_expected
+
+
+def test_usage():
+    solver = LearningSolver(components=[ObjectiveValueComponent()])
+    instance = get_knapsack_instance(GurobiPyomoSolver())
+    solver.solve(instance)
+    solver.fit([instance])
+    stats = solver.solve(instance)
+    assert stats["Lower bound"] == stats["Objective: predicted LB"]
+    assert stats["Upper bound"] == stats["Objective: predicted UB"]