Added unit test to test fallback to default config value when not configs are left after filtering for conditions.

Excluded log message branch from test coverage in utils.py.

Author: mwever

src/hypershap/utils.py

@@ -217,7 +217,7 @@ def _ensure_monotonicity(self, coalition: np.ndarray, value: float) -> float:
                 "Could not ensure monotonicity as none of the coalitions with one player less has been cached so far.",
             )
 
-        if value < monotone_value:
+        if value < monotone_value:  # pragma: no cover
             logger.debug(
                 "Ensured monotonicity with a sub-coalition's value. Increased the value of the current coalition from %s to %s.",
                 value,

tests/test_utils.py

@@ -12,6 +12,8 @@
     from hypershap import ExplanationTask
     from tests.fixtures.simple_setup import SimpleBlackboxFunction
 
+from ConfigSpace import Configuration
+
 from hypershap.task import BaselineExplanationTask
 from hypershap.utils import Aggregation, RandomConfigSpaceSearcher, evaluate_aggregation
 
@@ -144,3 +146,31 @@ def test_evaluate_aggregation() -> None:
     assert evaluate_aggregation(Aggregation.MAX, vals) == AGG_LIST[2]
     assert evaluate_aggregation(Aggregation.AVG, vals) == np.array(AGG_LIST).mean()
     assert abs(evaluate_aggregation(Aggregation.VAR, vals) - np.array(AGG_LIST).var()) < EPSILON
+
+
+def test_fallback_unfulfilled_conditions(simple_act_base_et: ExplanationTask) -> None:
+    """Test the fallback strategy when no configurations are left in random sample after filtering for conditions."""
+    bet = BaselineExplanationTask(
+        simple_act_base_et.config_space,
+        simple_act_base_et.surrogate_model,
+        simple_act_base_et.config_space.get_default_configuration(),
+    )
+    rcss = RandomConfigSpaceSearcher(bet)
+    rcss.random_sample = np.array([
+        Configuration(
+            configuration_space=simple_act_base_et.config_space,
+            values={
+                "a": 0.4,
+                "b": 0.1,
+            },
+        ).get_array(),
+        Configuration(
+            configuration_space=simple_act_base_et.config_space,
+            values={
+                "a": 0.5,
+                "b": 0.1,
+            },
+        ).get_array(),
+    ])
+    value = rcss.search(np.array([False, True]))
+    assert value is not None