Support Netcdf for native load test util

Native grid computation code didn't handle netcdf correctly as it assumed that
band path was sufficient, it's not for netdcf, going via BandInfo class and
RasterDatasetDataSource addresses this issue.

datacube/testutils/io.py

@@ -1,7 +1,7 @@
 import numpy as np
 
-from ..storage import reproject_and_fuse, measurement_paths
-from ..storage._rio import RasterioDataSource
+from ..storage import reproject_and_fuse, BandInfo
+from ..storage._rio import RasterioDataSource, RasterDatasetDataSource
 from ..utils.geometry._warp import resampling_s2rio
 from ..storage._read import rdr_geobox
 from ..utils.geometry import GeoBox
@@ -32,8 +32,8 @@ def get_crs(self):
         return self.crs
 
 
-def _raster_metadata(path, band=1):
-    source = RasterFileDataSource(path, band)
+def _raster_metadata(band):
+    source = RasterDatasetDataSource(band)
     with source.open() as rdr:
         return SimpleNamespace(dtype=rdr.dtype.name,
                                nodata=rdr.nodata,
@@ -45,12 +45,10 @@ def get_raster_info(ds, measurements=None):
     :param ds: Dataset
     :param measurements: List of band names to load
     """
-    paths = measurement_paths(ds)
-
     if measurements is None:
-        measurements = list(paths)
+        measurements = list(ds.type.measurements)
 
-    return {n: _raster_metadata(paths[n])
+    return {n: _raster_metadata(BandInfo(ds, n))
             for n in measurements}