to_scl_dilation_mask: raise error when input has multiple bands

related to Open-EO/openeo-geopyspark-driver#715

openeo_driver/ProcessGraphDeserializer.py

@@ -1995,6 +1995,13 @@ def mask_scl_dilation(args: Dict, env: EvalEnv):
 @process_registry_2xx.add_function(spec=read_spec("openeo-processes/experimental/to_scl_dilation_mask.json"))
 def to_scl_dilation_mask(args: ProcessArgs, env: EvalEnv):
     cube: DriverDataCube = args.get_required("data", expected_type=DriverDataCube)
+    if len(cube.metadata.band_names) != 1:
+        raise ProcessParameterInvalidException(
+            parameter="data",
+            process="to_scl_dilation_mask",
+            reason=f"The source data cube should only contain a single (SCL) band, but got {cube.metadata.band_names}.",
+        )
+
     # Get default values for other args from spec
     spec = read_spec("openeo-processes/experimental/to_scl_dilation_mask.json")
     defaults = {param["name"]: param["default"] for param in spec["parameters"] if "default" in param}

openeo_driver/dry_run.py

@@ -509,7 +509,7 @@ def filter_spatial(self, geometries):
         return cube._process(operation="filter_spatial", arguments={"geometries": geometries})
 
     def filter_bands(self, bands) -> 'DryRunDataCube':
-        return self._process("bands", bands)
+        return self._process("bands", bands, metadata=self.metadata.filter_bands(bands))
 
     def filter_properties(self, properties) -> 'DryRunDataCube':
         return self._process("properties", properties)

tests/test_views_execute.py

@@ -4215,3 +4215,27 @@ def test_to_scl_dilation_mask_defaults(api):
         "mask1_values": [2, 4, 5, 6, 7],
         "mask2_values": [3, 8, 9, 10, 11],
     }
+
+
+def test_to_scl_dilation_mask_multiple_bands(api):
+    """
+    input raster cube with multiple bands should raise error
+    """
+    res = api.result(
+        {
+            "loadcollection1": {
+                "process_id": "load_collection",
+                "arguments": {"id": "SENTINEL2_L2A_SENTINELHUB", "bands": ["B02", "B03", "SCL"]},
+            },
+            "to_scl_dilation_mask": {
+                "process_id": "to_scl_dilation_mask",
+                "arguments": {"data": {"from_node": "loadcollection1"}},
+                "result": True,
+            },
+        }
+    )
+    res.assert_error(
+        400,
+        "ProcessParameterInvalid",
+        message="The source data cube should only contain a single (SCL) band, but got ['B02', 'B03', 'SCL']",
+    )