Add sanity test to require elements entry when argument type=list (#66386)

* Require elements entry for lists

* Bulk add initial test/sanity/ignore.txt

changelogs/fragments/66386-ansible-test-module-validation-list-elements.yml

@@ -0,0 +1,2 @@
+minor_changes:
+- "ansible-test - the module validation code now checks whether ``elements`` is defined when ``type=list``"

docs/docsite/rst/dev_guide/testing_validate-modules.rst

@@ -123,6 +123,7 @@ Codes
   parameter-alias-repeated                                     Parameters           Error                  argument in argument_spec has at least one alias specified multiple times in aliases
   parameter-alias-self                                         Parameters           Error                  argument in argument_spec is specified as its own alias
   parameter-documented-multiple-times                          Documentation        Error                  argument in argument_spec with aliases is documented multiple times
+  parameter-list-no-elements                                   Parameters           Error                  argument in argument_spec "type" is specified as ``list`` without defining "elements"
   python-syntax-error                                          Syntax               Error                  Python ``SyntaxError`` while parsing module
   return-syntax-error                                          Documentation        Error                  ``RETURN`` is not valid YAML, ``RETURN`` fragments missing  or invalid
   subdirectory-missing-init                                    Naming               Error                  Ansible module subdirectories must contain an ``__init__.py``

test/lib/ansible_test/_data/sanity/validate-modules/validate_modules/main.py

@@ -1255,6 +1255,16 @@ class ModuleValidator(Validator):
                 _type_checker = module._CHECK_ARGUMENT_TYPES_DISPATCHER.get(_type)
 
             _elements = data.get('elements')
+            if (_type == 'list') and not _elements:
+                msg = "Argument '%s' in argument_spec" % arg
+                if context:
+                    msg += " found in %s" % " -> ".join(context)
+                msg += " defines type as list but elements is not defined"
+                self.reporter.error(
+                    path=self.object_path,
+                    code='parameter-list-no-elements',
+                    msg=msg
+                )
             if _elements:
                 if not callable(_elements):
                     module._CHECK_ARGUMENT_TYPES_DISPATCHER.get(_elements)