Reject blank positive imagery in training loop

backend/tests/test_belgium_training_loop.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import importlib.util
+from pathlib import Path
+
+
+SCRIPT = Path(__file__).parents[2] / "scripts" / "run_belgium_building_training_loop.py"
+SPEC = importlib.util.spec_from_file_location("training_loop", SCRIPT)
+assert SPEC and SPEC.loader
+MODULE = importlib.util.module_from_spec(SPEC)
+SPEC.loader.exec_module(MODULE)
+
+
+def test_training_command_is_cuda_deterministic_and_bound_to_frozen_inputs(tmp_path: Path) -> None:
+    command = MODULE.training_command(
+        "yolo",
+        model=tmp_path / "base.pt",
+        data=tmp_path / "dataset.yaml",
+        project=tmp_path / "runs",
+        name="iteration-001",
+        epochs=160,
+        seed=42,
+        batch=2,
+        workers=4,
+    )
+    assert command[:2] == ["yolo", "train"]
+    assert "device=0" in command
+    assert "deterministic=True" in command
+    assert "seed=42" in command
+    assert "epochs=160" in command
+    assert f"data={tmp_path / 'dataset.yaml'}" in command