Enhance CSV metadata with error tracking for mosaics and tiles

tests/test_session_download.py

@@ -0,0 +1,75 @@
+"""HTTP download result wiring in MachineSession."""
+
+from pathlib import Path
+
+import pytest
+import requests
+
+from spruce.download_result import PERMANENT_MISSING, TRANSIENT
+from spruce.session import MachineSession
+
+
+def _minimal_config() -> dict:
+    return {
+        "base_url": "http://127.0.0.1:8010/",
+        "image_base_url": "http://127.0.0.1:8011/",
+        "username": "u",
+        "password": "p",
+        "timeout": 10,
+        "request_delay": 0.0,
+        "workers": 2,
+    }
+
+
+def _machine() -> dict:
+    return {
+        "label": "T [AMR-0]",
+        "option_value": "x",
+        "machine_id": "0",
+    }
+
+
+def test_download_file_http_404_result(tmp_path: Path):
+    dest = tmp_path / "f.bin"
+    sess = MachineSession(_machine(), _minimal_config())
+
+    def fail_get(*_a, **_k):
+        r = requests.Response()
+        r.status_code = 404
+        r.url = "http://example/mosaic.jpg"
+        r.reason = "Not Found"
+        r.raise_for_status()
+
+    sess.http.get = fail_get  # type: ignore[method-assign]
+
+    res = sess.download_file("http://example/mosaic.jpg", dest, retries=1)
+    assert res.size == 0
+    assert res.status_code == 404
+    assert res.error_class == PERMANENT_MISSING
+    assert "404" in (res.error or "")
+
+
+def test_download_tile_row_on_failure(tmp_path: Path):
+    dest = tmp_path / "t.jpg"
+    tile = {
+        "scan_id": 1,
+        "row_index": 0,
+        "col_index": 0,
+        "x_mm": 0.0,
+        "y_mm": 0.0,
+        "url": "http://example/tile",
+    }
+    sess = MachineSession(_machine(), _minimal_config())
+
+    def fail_get(*_a, **_k):
+        r = requests.Response()
+        r.status_code = 500
+        r.url = "http://example"
+        r.reason = "Server Error"
+        r.raise_for_status()
+
+    sess.http.get = fail_get  # type: ignore[method-assign]
+    row = sess.download_tile(tile, dest, dry_run=False)
+    assert row["status"] == "failed"
+    assert row["error_code"] == "500"
+    assert row["error_class"] == TRANSIENT