Add test_convert_proj4_to_grid_mapping()

Function added to tests/test_exporters.py

pysteps/tests/test_exporters.py

@@ -13,6 +13,7 @@
 from pysteps.io.exporters import close_forecast_files
 from pysteps.io.exporters import export_forecast_dataset
 from pysteps.io.exporters import initialize_forecast_exporter_netcdf
+from pysteps.io.exporters import _convert_proj4_to_grid_mapping
 from pysteps.tests.helpers import get_precipitation_fields, get_invalid_mask
 
 # Test arguments
@@ -135,3 +136,61 @@ def test_io_export_netcdf_one_member_one_time_step(
         precip_new, _ = import_netcdf_pysteps(output_file_path, fillna=-1000)
         new_invalid_mask = precip_new == -1000
         assert (new_invalid_mask == invalid_mask).all()
+
+
+@pytest.mark.paramterize(
+    ["proj4str", "expected_value"],
+    [
+        (
+            "+proj=lcc +lat_1=49.83333333333334 +lat_2=51.16666666666666 +lat_0=50.797815 +lon_0=4.359215833333333 +x_0=649328 +y_0=665262 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs ",
+            (
+                "lcc",
+                "lambert_conformal_conic",
+                {
+                    "false_easting": 649328.0,
+                    "false_northing": 665262.0,
+                    "longitude_of_central_meridian": 4.359215833333333,
+                    "latitude_of_projection_origin": 50.797815,
+                    "standard_parallel": (49.83333333333334, 51.16666666666666),
+                    "reference_ellipsoid_name": "GRS80",
+                    "towgs84": "0,0,0,0,0,0,0",
+                },
+            ),
+        ),
+        (
+            "+proj=aea +lat_0=-37.852 +lon_0=144.752 +lat_1=-18.0 +lat_2=-36.0 +a=6378.137 +b=6356.752 +x_0=0 +y_0=0",
+            (
+                "proj",
+                "albers_conical_equal_area",
+                {
+                    "false_easting": 0.0,
+                    "false_northing": 0.0,
+                    "longitude_of_central_meridian": 144.752,
+                    "latitude_of_projection_origin": -37.852,
+                    "standard_parallel": (-18.0, -36.0),
+                },
+            ),
+        ),
+        (
+            "+proj=stere +lat_0=90 +lon_0=0.0 +lat_ts=60.0 +a=6378.137 +b=6356.752 +x_0=0 +y_0=0",
+            (
+                "polar_stereographic",
+                "polar_stereographic",
+                {
+                    "straight_vertical_longitude_from_pole": 0.0,
+                    "latitude_of_projection_origin": 90.0,
+                    "standard_parallel": 60.0,
+                    "false_easting": 0.0,
+                    "false_northing": 0.0,
+                },
+            ),
+        ),
+    ],
+)
+def test_convert_proj4_to_grid_mapping(proj4str, expected_value):
+    """
+    test the grid mapping in function _convert_proj4_to_grid_mapping()
+    """
+    output = _convert_proj4_to_grid_mapping(proj4str)
+
+    assert output == expected_value