MAINT: Code cleanup.

src/caosadvancedtools/table_json_conversion/table_generator.py

@@ -125,25 +125,38 @@ class TableTemplateGenerator(ABC):
                                                          path=[rt_name], foreign_keys=foreign_keys)
         return sheets
 
-    def _get_foreign_keys(self, keys: dict, path: list) -> list:
+    def _get_foreign_keys(self, keys: dict, path: list) -> list[list[str]]:
         """Return the foreign keys that are needed at the location to which path points.
 
 Returns
 -------
-foreign_keys: list
-  Contains strings or lists of strings.
+foreign_keys: list[list[str]]
+  Contains lists of strings, each element is the path to one foreign key.
 """
-        msg = f"A foreign key definition is missing for path:\n{path}\nKeys are:\n{keys}"
+        msg_missing = f"A foreign key definition is missing for path:\n{path}\nKeys are:\n{keys}"
+        orig_path = path.copy()
         while path:
             if keys is None or path[0] not in keys:
-                raise ValueError(msg)
+                raise ValueError(msg_missing)
             keys = keys[path[0]]
             path = path[1:]
         if isinstance(keys, dict) and "__this__" in keys:
-            return keys["__this__"]
-        if isinstance(keys, list):
-            return keys
-        raise ValueError(msg)
+            keys = keys["__this__"]
+        if isinstance(keys, str):
+            raise ValueError("Foreign keys must be a list of strings, but a single "
+                             "string was given:\n"
+                             f"{orig_path} -> {keys}")
+        if not isinstance(keys, list):
+            raise ValueError(msg_missing)
+
+        # Keys must be either all lists or all strings
+        types = {type(key) for key in keys}
+        if len(types) > 1:
+            raise ValueError("The keys of this path must bei either all lists or all strings:"
+                             f" {orig_path}")
+        if types.pop() is str:
+            keys = [[key] for key in keys]
+        return keys
 
     def _treat_schema_element(self, schema: dict, sheets: dict, path: list[str],
                               foreign_keys: Optional[dict] = None, level_in_sheet_name: int = 1,
@@ -204,13 +217,7 @@ foreign_keys: list
                     # and add the foreign keys that are necessary up to this point
                     for array_path in array_paths:
                         foreigns = self._get_foreign_keys(foreign_keys, array_path)
-                        if isinstance(foreigns, str):
-                            raise ValueError("Foreign keys must be a list of strings, but a single "
-                                             "string was given:\n"
-                                             f"{array_path} -> {foreigns}")
                         for foreign in foreigns:
-                            if isinstance(foreign, str):
-                                foreign = [foreign]
                             internal_key = p2s(array_path + foreign)
                             if internal_key in sheets[sheetname]:
                                 raise ValueError("The schema would lead to two columns with the "

unittests/table_json_conversion/test_table_template_generator.py

@@ -172,10 +172,10 @@ def test_generate_sheets_from_schema():
 def test_get_foreign_keys():
     generator = XLSXTemplateGenerator()
     fkd = {"Training": ['a']}
-    assert ['a'] == generator._get_foreign_keys(fkd, ['Training'])
+    assert [['a']] == generator._get_foreign_keys(fkd, ['Training'])
 
     fkd = {"Training": {"__this__": ['a']}}
-    assert ['a'] == generator._get_foreign_keys(fkd, ['Training'])
+    assert [['a']] == generator._get_foreign_keys(fkd, ['Training'])
 
     fkd = {"Training": {'hallo'}}
     with pytest.raises(ValueError, match=r"A foreign key definition is missing for path:\n\["
@@ -183,7 +183,7 @@ def test_get_foreign_keys():
         generator._get_foreign_keys(fkd, ['Training'])
 
     fkd = {"Training": {"__this__": ['a'], 'b': ['c']}}
-    assert ['c'] == generator._get_foreign_keys(fkd, ['Training', 'b'])
+    assert [['c']] == generator._get_foreign_keys(fkd, ['Training', 'b'])
 
     with pytest.raises(ValueError, match=r"A foreign key definition is missing for .*"):
         generator._get_foreign_keys({}, ['Training'])