Prioritize recall in failure-driven sampling

backend/tests/test_failure_driven_yolo_sampling.py

@@ -163,11 +163,39 @@ def test_sampling_targets_failed_calibration_contexts_without_using_protected_ti
     )
 
     assert paths.count(str(Path("/tmp/industry-pos.png").resolve())) == 5
-    assert paths.count(str(Path("/tmp/industry-neg.png").resolve())) == 6
+    assert paths.count(str(Path("/tmp/industry-neg.png").resolve())) == 1
     assert paths.count(str(Path("/tmp/suburban-pos.png").resolve())) == 3
     assert not any("protected" in path for path in paths)
     assert metadata["weak_recall_contexts"] == ["flanders:industrial"]
     assert metadata["weak_precision_contexts"] == ["flanders:industrial"]
+    assert metadata["recall_dominant_regions"] == ["flanders"]
+
+
+def test_recall_dominance_does_not_suppress_negatives_when_background_gate_failed() -> None:
+    manifest = {"samples": [
+        {"sample_slug": "positive", "split": "train", "region": "flanders", "context": "industrial"},
+        {"sample_slug": "negative", "split": "train", "region": "flanders", "context": "industrial-hard-negative"},
+    ]}
+    summary = {"tiles": [
+        {"sample_slug": "positive", "split": "train", "label_count": 1, "image_path": "/tmp/positive.png"},
+        {"sample_slug": "negative", "split": "train", "label_count": 0, "image_path": "/tmp/negative.png"},
+    ]}
+    assessment = {
+        "status": "continue_training_loop",
+        "gates": {"min_region_f1": .45, "min_region_precision": .5, "min_region_recall": .4,
+                  "max_pure_empty_false_positives": 0},
+        "calibration": {"regions": {
+            "flanders": {"f1": .25, "precision": .4, "recall": .2},
+        }},
+        "background": {"pure_empty_false_positives": 1},
+    }
+
+    paths, metadata = MODULE.build_sampling(
+        summary=summary, manifest=manifest, assessment=assessment, max_region_share=1.0,
+    )
+
+    assert paths.count(str(Path("/tmp/negative.png").resolve())) == 4
+    assert metadata["recall_dominant_regions"] == []
 
 
 def test_region_cap_drops_only_repeats_and_preserves_every_unique_tile() -> None: