dmrpp root and nested group parsing fix (#265)

* add root group and nested group support

* refactor functions for readability

* upgrade test suite

* resolve conflicts

* fix mypy types

* update dmrpp default fill_val

* update dmrpp default datapath

* add dedent() to pytest fixtures

* update function docs and releases

---------

Co-authored-by: Tom Nicholas <[email protected]>

docs/releases.rst

@@ -21,6 +21,8 @@ Deprecations
 Bug fixes
 ~~~~~~~~~
 
+- Handle root and nested groups with ``dmrpp`` backend (:pull:`265`)
+  By `Ayush Nag <https://github.com/ayushnag>`_.
 - Fixed bug with writing of `dimension_names` into zarr metadata.
   (:pull:`286`) By `Tom Nicholas <https://github.com/TomNicholas>`_.
 - Fixed bug causing CF-compliant variables not to be identified as coordinates (:pull:`191`)

virtualizarr/backend.py

@@ -127,10 +127,10 @@ def open_virtual_dataset(
         File path to open as a set of virtualized zarr arrays.
     filetype : FileType, default None
         Type of file to be opened. Used to determine which kerchunk file format backend to use.
-        Can be one of {'netCDF3', 'netCDF4', 'HDF', 'TIFF', 'GRIB', 'FITS', 'zarr_v3', 'kerchunk'}.
+        Can be one of {'netCDF3', 'netCDF4', 'HDF', 'TIFF', 'GRIB', 'FITS', 'dmrpp', 'zarr_v3', 'kerchunk'}.
         If not provided will attempt to automatically infer the correct filetype from header bytes.
     group : str, default is None
-        Path to the HDF5/netCDF4 group in the given file to open. Given as a str, supported by filetypes “netcdf4” and “hdf5”.
+        Path to the HDF5/netCDF4 group in the given file to open. Given as a str, supported by filetypes “netcdf4”, “hdf5”, and "dmrpp".
     drop_variables: list[str], default is None
         Variables in the file to drop before returning.
     loadable_variables: list[str], default is None