Add standardization test

tests/test_datastores.py

@@ -382,3 +382,24 @@ def test_plot_example_from_datastore(datastore_name):
 
     assert fig is not None
     assert fig.get_axes()
+
+
+@pytest.mark.parametrize("datastore_name", DATASTORES.keys())
+@pytest.mark.parametrize("category", ("state", "static"))
+def test_get_standardized_da(datastore_name, category):
+    """Check that dataarray is actually standardized when calling
+    get_dataarray with standardize=True"""
+    datastore = init_datastore_example(datastore_name)
+    ds_stats = datastore.get_standardization_dataarray(category=category)
+
+    mean = ds_stats[f"{category}_mean"]
+    std = ds_stats[f"{category}_std"]
+
+    non_standard_da = datastore.get_dataarray(
+        category=category, split="train", standardize=False
+    )
+    standard_da = datastore.get_dataarray(
+        category=category, split="train", standardize=True
+    )
+
+    assert np.allclose(standard_da, (non_standard_da - mean) / std, atol=1e-6)