fix: Correct the test by replacing numpy array to dask array to simul…

…ate the real case data

satpy/tests/compositor_tests/test_lightning.py

@@ -21,6 +21,7 @@
 import datetime
 import logging
 
+import dask.array as da
 import numpy as np
 import pytest
 import xarray as xr
@@ -37,7 +38,7 @@ def test_flash_age_compositor():
     attrs_flash_age = {"variable_name": "flash_time","name": "flash_time",
                        "start_time": datetime.datetime(2024, 8, 1, 10, 50, 0),
                        "end_time": datetime.datetime(2024, 8, 1, 11, 0, 0),"reader": "li_l2_nc"}
-    flash_age_value = np.array(["2024-08-01T09:00:00",
+    flash_age_value = da.array(["2024-08-01T09:00:00",
             "2024-08-01T10:00:00", "2024-08-01T10:30:00","2024-08-01T11:00:00"], dtype="datetime64[ns]")
     flash_age = xr.DataArray(
     flash_age_value,
@@ -52,7 +53,7 @@ def test_flash_age_compositor():
                        "standard_name": "ligtning_time"
                        }
     expected_array = xr.DataArray(
-    np.array([0.0,0.5,1.0]),
+    da.array([0.0,0.5,1.0]),
     dims=["y"],
     coords={
         "crs": "8B +proj=longlat +ellps=WGS84 +type=crs"
@@ -69,7 +70,7 @@ def test_empty_array_error(caplog):
                        "start_time": np.datetime64(datetime.datetime(2024, 8, 1, 10, 0, 0)),
                        "end_time": datetime.datetime(2024, 8, 1, 11, 0, 0),
                        "reader": "li_l2_nc"}
-    flash_age_value = np.array(["2024-08-01T09:00:00"], dtype="datetime64[ns]")
+    flash_age_value = da.array(["2024-08-01T09:00:00"], dtype="datetime64[ns]")
     flash_age = xr.DataArray(
     flash_age_value,
     dims=["y"],