Bring _utils.py up to 100% coverage

Author: tennlee

packages/data/src/pyearthtools/data/transforms/normalisation/_utils.py

@@ -21,17 +21,21 @@
 def format_class_name(class_to_find: object) -> list[str]:
     """
     Format class name for use in normalisation caching
+    Strip out 'pyearthtools.data' from class names and use the rest
+    as the identifiers
 
     Args:
         class_to_find (str): Class to find name for
 
     Returns:
         list[str]: Components of class name
     """
+
+    # e.g. "<class 'pyearthtools.data.time.Petdt'>"
     class_str = str(class_to_find.__class__).split("'")[1]
     class_str = class_str.replace(CLASS_NAME_TO_TRIM, "")
     class_str_list = class_str.strip().split(".")
 
-    if "" in class_str_list:
-        class_str_list.remove("")
-    return []
+    class_str_list = [e for e in class_str_list if e != ""]
+
+    return class_str_list

packages/data/tests/data/transform/normalisation/test_nutils.py

@@ -0,0 +1,22 @@
+# Copyright Commonwealth of Australia, Bureau of Meteorology 2025.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from pyearthtools.data.transforms.normalisation import _utils
+import pyearthtools.data.time
+
+def test_format_class_name():
+
+    obj = pyearthtools.data.time.Petdt('2010-01-01')
+    result = _utils.format_class_name(obj)
+    assert result == ['time', 'Petdt']