Remove obsolete extractor classes

tests/test_extractors.py

@@ -1,34 +0,0 @@
-#  MIPLearn: Extensible Framework for Learning-Enhanced Mixed-Integer Optimization
-#  Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
-#  Released under the modified BSD license. See COPYING.md for more details.
-import numpy as np
-
-from miplearn.extractors import InstanceFeaturesExtractor
-from miplearn.problems.knapsack import KnapsackInstance
-from miplearn.solvers.learning import LearningSolver
-
-
-def _get_instances():
-    instances = [
-        KnapsackInstance(
-            weights=[1.0, 2.0, 3.0],
-            prices=[10.0, 20.0, 30.0],
-            capacity=2.5,
-        ),
-        KnapsackInstance(
-            weights=[3.0, 4.0, 5.0],
-            prices=[20.0, 30.0, 40.0],
-            capacity=4.5,
-        ),
-    ]
-    models = [instance.to_model() for instance in instances]
-    solver = LearningSolver()
-    for (i, instance) in enumerate(instances):
-        solver.solve(instances[i], models[i])
-    return instances, models
-
-
-def test_instance_features_extractor():
-    instances, models = _get_instances()
-    features = InstanceFeaturesExtractor().extract(instances)
-    assert features.shape == (2, 3)