add numpybatch convert satellite test

tests/numpy_batch/test_satellite.py

@@ -0,0 +1,42 @@
+
+import numpy as np
+import pandas as pd
+import xarray as xr
+
+import pytest
+
+from ocf_data_sampler.numpy_batch import convert_satellite_to_numpy_batch
+
+from ocf_datapipes.batch import BatchKey
+
+
+@pytest.fixture(scope="module")
+def da_sat_like():
+    """Create dummy data which looks like satellite data"""
+    x = np.arange(-100, 100, 10)
+    y = np.arange(-100, 100, 10)
+    datetimes = pd.date_range("2024-01-01 12:00", "2024-01-02 12:30", freq="5min")
+    channels = ["VIS008", "IR016"]
+
+    da_sat = xr.DataArray(
+        np.random.normal(size=(len(datetimes), len(channels), len(x), len(y))),
+        coords=dict(
+            time_utc=(["time_utc"], datetimes),
+            channel=(["channel"], channels),
+            x_geostationary=(["x_geostationary"], x),
+            y_geostationary=(["y_geostationary"], y),
+        )
+    )
+    return da_sat
+
+
+def test_convert_satellite_to_numpy_batch(da_sat_like):
+
+    # Call the function
+    numpy_batch = convert_satellite_to_numpy_batch(da_sat_like)
+
+    # Assert the output type
+    assert isinstance(numpy_batch, dict)
+
+    # Assert the shape of the numpy batch
+    assert (numpy_batch[BatchKey.satellite_actual] == da_sat_like.values).all()