correct overlapping checkpoint evaluation

tests/test_derive_yolo_nonoverlap_evaluation_view.py

@@ -0,0 +1,49 @@
+from pathlib import Path
+
+from PIL import Image
+
+from scripts.derive_yolo_nonoverlap_evaluation_view import (
+    image_has_low_visual_variance,
+    select_nonoverlap_tiles,
+)
+
+
+def tile(name: str, index: int, split: str = "val") -> dict[str, object]:
+    return {
+        "image_path": f"/data/sample_{index:04d}_{name}.png",
+        "tile_index": index,
+        "sample_slug": "sample",
+        "split": split,
+        "kept": True,
+    }
+
+
+def test_select_nonoverlap_tiles_keeps_complete_512_grid() -> None:
+    tiles = [
+        tile("r0_c0", 0),
+        tile("r0_c256", 1),
+        tile("r0_c512", 2),
+        tile("r256_c0", 3),
+        tile("r256_c256", 4),
+        tile("r256_c512", 5),
+        tile("r512_c0", 6),
+        tile("r512_c256", 7),
+        tile("r512_c512", 8),
+        tile("r0_c0", 9, split="train"),
+    ]
+
+    selected = select_nonoverlap_tiles(tiles, 512)
+
+    assert [item["tile_index"] for item in selected] == [0, 2, 6, 8]
+
+
+def test_image_has_low_visual_variance_rejects_blank_no_data(tmp_path: Path) -> None:
+    blank = tmp_path / "blank.png"
+    real = tmp_path / "real.png"
+    Image.new("L", (8, 8), color=255).save(blank)
+    image = Image.new("L", (8, 8), color=100)
+    image.putpixel((0, 0), 120)
+    image.save(real)
+
+    assert image_has_low_visual_variance(blank, 3) is True
+    assert image_has_low_visual_variance(real, 3) is False

tests/test_evaluate_yolo_checkpoint_matrix.py

@@ -17,7 +17,8 @@ def test_dataset_overlap_evidence_marks_repeated_validation_rows(
 
     assert evidence["status"] == "overlapping"
     assert evidence["overlap_pixels"] == 256
-    assert evidence["validation_rows_independent"] is False
+    assert evidence["validation_tiles_non_overlapping"] is False
+    assert evidence["statistical_independence_established"] is False
 
 
 def test_dataset_overlap_evidence_is_explicit_when_summary_missing(
@@ -26,4 +27,21 @@ def test_dataset_overlap_evidence_is_explicit_when_summary_missing(
     evidence = dataset_overlap_evidence(tmp_path / "dataset.yaml")
 
     assert evidence["status"] == "unavailable"
-    assert evidence["validation_rows_independent"] is None
+    assert evidence["validation_tiles_non_overlapping"] is None
+    assert evidence["statistical_independence_established"] is False
+
+
+def test_nonoverlap_does_not_overclaim_statistical_independence(
+    tmp_path: Path,
+) -> None:
+    dataset_yaml = tmp_path / "dataset.yaml"
+    dataset_yaml.write_text("path: .\nval: images/val\n", encoding="utf-8")
+    (tmp_path / "yolo_tile_dataset_summary.json").write_text(
+        json.dumps({"tile_size": 512, "stride": 512}), encoding="utf-8"
+    )
+
+    evidence = dataset_overlap_evidence(dataset_yaml)
+
+    assert evidence["validation_tiles_non_overlapping"] is True
+    assert evidence["statistical_independence_established"] is False
+    assert "not established" in evidence["interpretation"]