Tile large DHMV coverage requests

backend/tests/test_sprint205_dhmv_terrain.py

@@ -167,6 +167,29 @@ def test_dhmv_request_rejects_unsafe_size_and_resolution() -> None:
         DhmvAcquireRequest.model_validate(payload.model_dump())
 
 
+def test_dhmv_large_scope_is_bounded_into_mosaicable_wcs_tiles() -> None:
+    prepared = DhmvAcquisitionService._prepared_request(
+        lambert_bbox_payload(side_m=15_000.0),
+        Settings(_env_file=None),
+    )
+
+    tile_bounds = DhmvAcquisitionService._tile_bounds(prepared)
+
+    assert len(tile_bounds) == 4
+    assert all(bounds[2] - bounds[0] <= 10_000.0 for bounds in tile_bounds)
+    assert all(bounds[3] - bounds[1] <= 10_000.0 for bounds in tile_bounds)
+
+    left = elevation_tiff(left=200_000, top=210_100, width=20, height=20)
+    right = elevation_tiff(left=200_100, top=210_100, width=20, height=20)
+    mosaic = DhmvAcquisitionService._mosaic_geotiffs([left, right])
+    with MemoryFile(mosaic) as memory, memory.open() as dataset:
+        assert dataset.crs.to_epsg() == 31370
+        assert dataset.res == pytest.approx((5.0, 5.0))
+        assert dataset.width == 40
+        assert dataset.height == 20
+        assert dataset.nodata == -9999.0
+
+
 def test_dhmv_multipart_geotiff_is_extracted_and_invalid_response_fails_closed() -> None:
     tiff = elevation_tiff(left=200_000, top=210_100, width=20, height=20)
     multipart, content_type = multipart_tiff(tiff)