Primal: Add end-to-end tests

tests/components/test_primal.py

@@ -6,11 +6,14 @@ from unittest.mock import Mock
 
 import numpy as np
 from numpy.testing import assert_array_equal
+from scipy.stats import randint
 
-from miplearn import Classifier
+from miplearn import Classifier, LearningSolver, GurobiSolver, GurobiPyomoSolver
 from miplearn.classifiers.threshold import Threshold
 from miplearn.components.primal import PrimalSolutionComponent
+from miplearn.problems.tsp import TravelingSalesmanGenerator
 from miplearn.types import TrainingSample, Features
+from tests.fixtures.knapsack import get_knapsack_instance
 
 
 def test_xy_sample_with_lp_solution() -> None:
@@ -210,3 +213,19 @@ def test_fit_xy():
         thr.fit.assert_called_once()
         assert_array_equal(x[category], thr.fit.call_args[0][1])
         assert_array_equal(y[category], thr.fit.call_args[0][2])
+
+
+def test_usage():
+    solver = LearningSolver(
+        components=[
+            PrimalSolutionComponent(),
+        ]
+    )
+    gen = TravelingSalesmanGenerator(n=randint(low=5, high=6))
+    instance = gen.generate(1)[0]
+    solver.solve(instance)
+    solver.fit([instance])
+    stats = solver.solve(instance)
+    assert stats["Primal: free"] == 0
+    assert stats["Primal: one"] + stats["Primal: zero"] == 10
+    assert stats["Lower bound"] == stats["Warm start value"]