Remove dimensions implicit default

nomenclature/definition.py

@@ -66,11 +66,11 @@ def __init__(self, path, dimensions=None):
         self.dimensions = (
             dimensions
             or self.config.dimensions
-            or [
-                "region",
-                "variable",
-            ]
+            or [x.stem for x in path.iterdir() if x.is_dir()]
         )
+        if not self.dimensions:
+            raise ValueError("No dimensions specified in data structure.")
+
         for dim in self.dimensions:
             codelist_cls = SPECIAL_CODELIST.get(dim, CodeList)
             self.__setattr__(

nomenclature/testing.py

@@ -5,6 +5,7 @@
 import yaml
 
 from nomenclature.definition import DataStructureDefinition
+from nomenclature.config import NomenclatureConfig
 from nomenclature.processor import (
     DataValidator,
     RegionProcessor,
@@ -144,8 +145,12 @@ def assert_valid_structure(
             f"Definitions directory not found: {path / definitions}"
         )
 
-    if dimensions == ():  # if "dimensions" were not specified
-        dimensions = [x.stem for x in (path / definitions).iterdir() if x.is_dir()]
+    if not dimensions:  # if "dimensions" were not specified
+        dimensions = (
+            NomenclatureConfig.from_file(path / "nomenclature.yaml").dimensions
+            if (path / "nomenclature.yaml").is_file()
+            else [x.stem for x in (path / definitions).iterdir() if x.is_dir()]
+        )
         if not dimensions:
             raise FileNotFoundError(
                 f"`definitions` directory is empty: {path / definitions}"

tests/data/region_processing/external_repo_test/nomenclature.yaml

@@ -1,3 +1,6 @@
+dimensions:
+  - region
+  - variable
 repositories:
   common-definitions:
     url: https://github.com/IAMconsortium/common-definitions.git/

tests/test_definition.py

@@ -34,7 +34,7 @@ def test_nonexisting_path_raises():
 
 def test_empty_codelist_raises():
     """Check that initializing a DataStructureDefinition with empty CodeList raises"""
-    match = "Empty codelist: region, variable"
+    match = "No dimensions specified in data structure."
     with pytest.raises(ValueError, match=match):
         DataStructureDefinition(TEST_DATA_DIR / "codelist" / "simple_codelist")
 
@@ -134,8 +134,7 @@ def test_create_yaml_from_xlsx(input_file, attrs, exp_file, tmpdir):
 
     with open(file, "r", encoding="utf-8") as f:
         obs = f.read()
-    with open(TEST_DATA_DIR / "io" / "excel_io" / exp_file, "r",
-              encoding="utf-8") as f:
+    with open(TEST_DATA_DIR / "io" / "excel_io" / exp_file, "r", encoding="utf-8") as f:
         exp = f.read()
 
     assert obs == exp