From 31edac7eb9eeb4af1ffd99bd30bd9df8cd482e3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Mon, 10 Mar 2025 15:42:53 +0100
Subject: [PATCH 1/7] move generation of _choice suffix

trying to generate polymorphic protobuf messages leads to the necessary generation of choice messages.
naming them is now moved to the naming.py utilities
---
 aas_core_codegen/protobuf/common.py           | 21 +++++++++-----
 aas_core_codegen/protobuf/description.py      |  4 +--
 aas_core_codegen/protobuf/main.py             |  6 ++--
 aas_core_codegen/protobuf/naming.py           |  9 ++----
 .../protobuf/structure/_generate.py           | 29 ++++++++++++-------
 5 files changed, 40 insertions(+), 29 deletions(-)

diff --git a/aas_core_codegen/protobuf/common.py b/aas_core_codegen/protobuf/common.py
index 0649218c..4afdeeef 100644
--- a/aas_core_codegen/protobuf/common.py
+++ b/aas_core_codegen/protobuf/common.py
@@ -138,32 +138,37 @@ def generate_type(type_annotation: intermediate.TypeAnnotationUnion) -> Stripped
             return PRIMITIVE_TYPE_MAP[our_type.constrainee]
 
         elif isinstance(our_type, intermediate.Class):
+
             message_name = proto_naming.class_name(our_type.name)
+
             if len(our_type.concrete_descendants) > 0:
                 # NOTE (TomGneuss):
-                # We add the suffix "_choice" to the type name because this type
-                # (either abstract or concrete) has concrete subtypes.
-                # Thus, a choice-object (with that suffix) will be generated and must
-                # be used here.
-                message_name = Identifier(message_name + "_choice")
+                # If the current type is either interface, abstract, or concrete class
+                # and has concrete descendants, it must have the name of a
+                # choice-message to simulate polymorphism
+                message_name = proto_naming.interface_name(our_type.name)
 
             return Stripped(message_name)
 
     elif isinstance(type_annotation, intermediate.ListTypeAnnotation):
         item_type = generate_type(type_annotation=type_annotation.items)
 
+        # NOTE (TomGneuss):
+        # Careful: This does not yet cover the hypothetical scenario where
+        # type_annotation.items is of type intermediate.OptionalTypeAnnotation.
+        # As below, constructs like "repeated optional <type> <name>" are invalid.
         return Stripped(f"repeated {item_type}")
 
     elif isinstance(type_annotation, intermediate.OptionalTypeAnnotation):
-        value = generate_type(type_annotation=type_annotation.value)
+        value_name = generate_type(type_annotation=type_annotation.value)
 
         # NOTE (TomGneuss):
         # Careful: do not generate "optional" keyword for list-type elements since
         # otherwise we get invalid constructs like "optional repeated <type> <name>".
         if isinstance(type_annotation.value, intermediate.ListTypeAnnotation):
-            return Stripped(f"{value}")
+            return Stripped(f"{value_name}")
         else:
-            return Stripped(f"optional {value}")
+            return Stripped(f"optional {value_name}")
 
     else:
         assert_never(type_annotation)
diff --git a/aas_core_codegen/protobuf/description.py b/aas_core_codegen/protobuf/description.py
index 1f2e039f..c9256a24 100644
--- a/aas_core_codegen/protobuf/description.py
+++ b/aas_core_codegen/protobuf/description.py
@@ -180,7 +180,7 @@ def transform_reference_to_our_type_in_doc(
                 # NOTE (mristin, 2021-12-25):
                 # We do not generate ProtoBuf code for abstract classes, so we have to refer
                 # to the interface.
-                name = proto_naming.class_name(element.our_type.name)
+                name = proto_naming.interface_name(element.our_type.name)
 
             elif isinstance(element.our_type, intermediate.ConcreteClass):
                 # NOTE (mristin, 2021-12-25):
@@ -227,7 +227,7 @@ def transform_reference_to_attribute_in_doc(
             if isinstance(element.reference.cls, intermediate.AbstractClass):
                 # We do not generate ProtoBuf code for abstract classes, so we have to refer
                 # to the interface.
-                name_of_our_type = proto_naming.class_name(element.reference.cls.name)
+                name_of_our_type = proto_naming.interface_name(element.reference.cls.name)
             elif isinstance(element.reference.cls, intermediate.ConcreteClass):
                 # NOTE (mristin, 2021-12-25):
                 # Though a concrete class can have multiple descendants and the writer
diff --git a/aas_core_codegen/protobuf/main.py b/aas_core_codegen/protobuf/main.py
index 298f379b..b4a38ff0 100644
--- a/aas_core_codegen/protobuf/main.py
+++ b/aas_core_codegen/protobuf/main.py
@@ -66,16 +66,16 @@ def execute(context: run.Context, stdout: TextIO, stderr: TextIO) -> int:
         )
         return 1
 
-    namespace_key = specific_implementations.ImplementationKey("namespace.txt")
+    namespace_key = specific_implementations.ImplementationKey("package.txt")
     namespace_text = context.spec_impls.get(namespace_key, None)
     if namespace_text is None:
-        stderr.write(f"The namespace snippet is missing: {namespace_key}\n")
+        stderr.write(f"The package snippet is missing: {namespace_key}\n")
         return 1
 
     if not proto_common.NAMESPACE_IDENTIFIER_RE.fullmatch(namespace_text):
         stderr.write(
             f"The text from the snippet {namespace_key} "
-            f"is not a valid namespace identifier: {namespace_text!r}\n"
+            f"is not a valid package identifier: {namespace_text!r}\n"
         )
         return 1
 
diff --git a/aas_core_codegen/protobuf/naming.py b/aas_core_codegen/protobuf/naming.py
index d0761b50..189e2578 100644
--- a/aas_core_codegen/protobuf/naming.py
+++ b/aas_core_codegen/protobuf/naming.py
@@ -13,9 +13,10 @@ def interface_name(identifier: Identifier) -> Identifier:
     """
     Generate a ProtoBuf name for an interface based on its meta-model ``identifier``.
 
-    This method is not to be used because proto3 does not support interfaces.
+    Since proto3 does not directly support interfaces, but only one-of messages
+    (commonly suffixed "_choice"), these names are generated here.
     """
-    raise NotImplementedError("Interfaces are not supported by proto3.")
+    return aas_core_codegen.naming.capitalized_camel_case(identifier) + "_choice"
 
 
 def enum_name(identifier: Identifier) -> Identifier:
@@ -44,10 +45,6 @@ def enum_literal_name(identifier: Identifier) -> Identifier:
     return aas_core_codegen.naming.upper_snake_case(identifier)
 
 
-@ensure(
-    lambda result: "_" not in result,
-    "No underscode allowed so that we can attached our own suffixes such as ``_choice``",
-)
 def class_name(identifier: Identifier) -> Identifier:
     """
     Generate a ProtoBuf name for a class based on its meta-model ``identifier``.
diff --git a/aas_core_codegen/protobuf/structure/_generate.py b/aas_core_codegen/protobuf/structure/_generate.py
index 0315da8a..645101b3 100644
--- a/aas_core_codegen/protobuf/structure/_generate.py
+++ b/aas_core_codegen/protobuf/structure/_generate.py
@@ -244,7 +244,7 @@ def _generate_enum(
 
     # write enum and its name
     writer.write(f"enum {name} {{\n")
-    # write at least the unspecified enum entry
+    # write at least the default enum literal
     writer.write(textwrap.indent(f"{proto_naming.enum_name(name)}_UNSPECIFIED = 0;", I))
 
     if len(enum.literals) == 0:
@@ -275,13 +275,16 @@ def _generate_enum(
             writer.write(textwrap.indent(literal_comment, I))
             writer.write("\n")
 
-        # Enums cannot have string-values assigned to them in proto3. Instead, they each get assigned
-        # an ID that is used for (de-)serialization.
-        # If that ID is re-assigned to another literal in the same enum in a later version, a system using the
-        # old version will (de-)serialize that literal differently. Hence, hope that the order of writing the literals
-        # stays the same in each build so that one literal always gets the same ID. Otherwise, don't mix versions.
-        # With each version, compare to the previous one and assign same ID.
-        # With each version, add a `reserved`-statement for deleted literals and their IDs.
+        # Note (TomGneuss):
+        # Enums cannot have string-values assigned to them in proto3. Instead, they
+        # each get an ID assigned that is used for (de-)serialization. If that ID is
+        # re-assigned to another literal in the same enum in a later version, a system
+        # using the old version will (de-)serialize that literal differently.
+        # Hence, hope that the order of writing the literals stays the same in each
+        # build so that existing literals always get the same ID (backward compatible).
+        # Otherwise, don't mix versions. Ideally, with each version, compare to the
+        # previous one and assign the same ID. With every new version, add a
+        # `reserved`-statement for deleted literals and their IDs.
         writer.write(
             textwrap.indent(
                 f"""\
@@ -383,6 +386,10 @@ def _generate_choice_class(cls: intermediate.ClassUnion) -> Stripped:
 
     concrete_classes = []
     if isinstance(cls, intermediate.ConcreteClass):
+        # NOTE (TomGneuss):
+        # The type cls has concrete descendants but is itself concrete, so it must
+        # be listed as one of its own subtypes in the choice message because that
+        # is how proto3 tries to model polymorphism
         concrete_classes.append(cls)
 
     concrete_classes.extend(cls.concrete_descendants)
@@ -392,7 +399,7 @@ def _generate_choice_class(cls: intermediate.ClassUnion) -> Stripped:
         subtype_name = proto_naming.property_name(subtype.name)
         fields.append(Stripped(f"{subtype_type} {subtype_name} = {j + 1};"))
 
-    message_name = Identifier(proto_naming.class_name(cls.name) + "_choice")
+    message_name = Identifier(proto_naming.interface_name(cls.name))
 
     fields_joined = "\n".join(fields)
 
@@ -425,6 +432,7 @@ def generate(
 
     errors = []  # type: List[Error]
 
+    # generate message definitions for concrete classes and enums first
     for our_type in symbol_table.our_types:
         if not isinstance(
             our_type,
@@ -467,6 +475,8 @@ def generate(
         else:
             assert_never(our_type)
 
+    # generate choice messages for all interfaces and abstract or concrete classes
+    # that have concrete descendants
     for cls in symbol_table.classes:
         if len(cls.concrete_descendants) > 0:
             code_blocks.append(_generate_choice_class(cls))
@@ -484,7 +494,6 @@ def generate(
 
 package {namespace};
 
-
 {code_blocks_joined}"""
         ),
         proto_common.WARNING,

From 103c6a156f3573d5c8257911b58f2c0c68e9bf54 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Tue, 11 Mar 2025 07:53:03 +0100
Subject: [PATCH 2/7] move test cases for protobuf

the directory structure for the protobuf generator test cases is now aligned with the other generators
---
 .../expected_output/stdout.txt                |   0
 .../expected_output/types.proto               | 158 +++++++++---------
 .../input/snippets/package.txt                |   1 +
 .../expected_output/stdout.txt                |   0
 .../expected_output/types.proto               |   0
 .../input/snippets/package.txt}               |   0
 .../meta_model.py                             |   0
 .../expected_output/stdout.txt                |   0
 .../expected_output/types.proto               |   0
 .../input/snippets/package.txt}               |   0
 .../meta_model.py                             |   0
 .../expected_output/stdout.txt                |   0
 .../expected_output/types.proto               |   0
 .../input/snippets/package.txt}               |   0
 .../concrete_class_with_enum/meta_model.py    |   0
 .../expected_output/stdout.txt                |   0
 .../expected_output/types.proto               |   0
 .../input/snippets/package.txt}               |   0
 .../meta_model.py                             |   0
 .../expected_output/stdout.txt                |   0
 .../expected_output/types.proto               |   0
 .../input/snippets/package.txt}               |   0
 .../meta_model.py                             |   0
 .../input/snippets/namespace.txt              |   1 -
 24 files changed, 80 insertions(+), 80 deletions(-)
 rename test_data/proto/test_main/{expected => }/aas_core_meta.v3/expected_output/stdout.txt (100%)
 rename test_data/proto/test_main/{expected => }/aas_core_meta.v3/expected_output/types.proto (94%)
 create mode 100644 test_data/proto/test_main/aas_core_meta.v3/input/snippets/package.txt
 rename test_data/proto/test_main/{expected => }/abstract_and_concrete_classes/expected_output/stdout.txt (100%)
 rename test_data/proto/test_main/{expected => }/abstract_and_concrete_classes/expected_output/types.proto (100%)
 rename test_data/proto/test_main/{expected/abstract_and_concrete_classes/input/snippets/namespace.txt => abstract_and_concrete_classes/input/snippets/package.txt} (100%)
 rename test_data/proto/test_main/{expected => }/abstract_and_concrete_classes/meta_model.py (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_descendants/expected_output/stdout.txt (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_descendants/expected_output/types.proto (100%)
 rename test_data/proto/test_main/{expected/concrete_class_with_descendants/input/snippets/namespace.txt => concrete_class_with_descendants/input/snippets/package.txt} (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_descendants/meta_model.py (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_enum/expected_output/stdout.txt (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_enum/expected_output/types.proto (100%)
 rename test_data/proto/test_main/{expected/concrete_class_with_enum/input/snippets/namespace.txt => concrete_class_with_enum/input/snippets/package.txt} (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_enum/meta_model.py (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_list_of_instances/expected_output/stdout.txt (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_list_of_instances/expected_output/types.proto (100%)
 rename test_data/proto/test_main/{expected/concrete_class_with_list_of_instances/input/snippets/namespace.txt => concrete_class_with_list_of_instances/input/snippets/package.txt} (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_list_of_instances/meta_model.py (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_primitive_attributes/expected_output/stdout.txt (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_primitive_attributes/expected_output/types.proto (100%)
 rename test_data/proto/test_main/{expected/concrete_class_with_primitive_attributes/input/snippets/namespace.txt => concrete_class_with_primitive_attributes/input/snippets/package.txt} (100%)
 rename test_data/proto/test_main/{expected => }/concrete_class_with_primitive_attributes/meta_model.py (100%)
 delete mode 100644 test_data/proto/test_main/expected/aas_core_meta.v3/input/snippets/namespace.txt

diff --git a/test_data/proto/test_main/expected/aas_core_meta.v3/expected_output/stdout.txt b/test_data/proto/test_main/aas_core_meta.v3/expected_output/stdout.txt
similarity index 100%
rename from test_data/proto/test_main/expected/aas_core_meta.v3/expected_output/stdout.txt
rename to test_data/proto/test_main/aas_core_meta.v3/expected_output/stdout.txt
diff --git a/test_data/proto/test_main/expected/aas_core_meta.v3/expected_output/types.proto b/test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto
similarity index 94%
rename from test_data/proto/test_main/expected/aas_core_meta.v3/expected_output/types.proto
rename to test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto
index 9fa643db..6a20f479 100644
--- a/test_data/proto/test_main/expected/aas_core_meta.v3/expected_output/types.proto
+++ b/test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto
@@ -5,7 +5,7 @@
 
 syntax = "proto3";
 
-package aas_core3;
+package aas_core.aas3_0;
 
 
 /// <summary>
@@ -40,7 +40,7 @@ message Extension {
   /// <ul>
   ///   <li>
   ///     Constraint AASd-077:
-  ///     The name of an extension (Extension/name) within <see cref="Aas.HasExtensions" /> needs
+  ///     The name of an extension (Extension/name) within <see cref="Aas.HasExtensions_choice" /> needs
   ///     to be unique.
   ///   </li>
   /// </ul>
@@ -164,7 +164,7 @@ enum QualifierKind {
 
   /// <summary>
   /// qualifies the semantic definition the element is referring to
-  /// (<see cref="Aas.HasSemantics.semantic_id" />)
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />)
   /// </summary>
   Qualifierkind_CONCEPT_QUALIFIER = 2;
 
@@ -271,7 +271,7 @@ message AssetAdministrationShell {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -284,8 +284,8 @@ message AssetAdministrationShell {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -585,7 +585,7 @@ message Submodel {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -598,8 +598,8 @@ message Submodel {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -714,7 +714,7 @@ message RelationshipElement {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -727,8 +727,8 @@ message RelationshipElement {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -863,23 +863,23 @@ enum AasSubmodelElements {
 ///   <li>
 ///     Constraint AASd-107:
 ///     If a first level child element in a <see cref="Aas.SubmodelElementList" /> has
-///     a <see cref="Aas.HasSemantics.semantic_id" /> it
+///     a <see cref="Aas.HasSemantics_choice.semantic_id" /> it
 ///     shall be identical to <see cref="Aas.SubmodelElementList.semantic_id_list_element" />.
 ///   </li>
 ///   <li>
 ///     Constraint AASd-114:
 ///     If two first level child elements in a <see cref="Aas.SubmodelElementList" /> have
-///     a <see cref="Aas.HasSemantics.semantic_id" /> then they shall be identical.
+///     a <see cref="Aas.HasSemantics_choice.semantic_id" /> then they shall be identical.
 ///   </li>
 ///   <li>
 ///     Constraint AASd-115:
 ///     If a first level child element in a <see cref="Aas.SubmodelElementList" /> does not
-///     specify a <see cref="Aas.HasSemantics.semantic_id" /> then the value is assumed to be
+///     specify a <see cref="Aas.HasSemantics_choice.semantic_id" /> then the value is assumed to be
 ///     identical to <see cref="Aas.SubmodelElementList.semantic_id_list_element" />.
 ///   </li>
 ///   <li>
 ///     Constraint AASd-120:
-///     The <see cref="Aas.SubmodelElementList.id_short" /> of a <see cref="Aas.SubmodelElement" /> being a direct child of a
+///     The <see cref="Aas.SubmodelElementList.id_short" /> of a <see cref="Aas.SubmodelElement_choice" /> being a direct child of a
 ///     <see cref="Aas.SubmodelElementList" /> shall not be specified.
 ///   </li>
 ///   <li>
@@ -912,7 +912,7 @@ message SubmodelElementList {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -925,8 +925,8 @@ message SubmodelElementList {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1049,7 +1049,7 @@ message SubmodelElementCollection {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1062,8 +1062,8 @@ message SubmodelElementCollection {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1168,7 +1168,7 @@ message Property {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1181,8 +1181,8 @@ message Property {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1300,7 +1300,7 @@ message MultiLanguageProperty {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1313,8 +1313,8 @@ message MultiLanguageProperty {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1414,7 +1414,7 @@ message Range {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1427,8 +1427,8 @@ message Range {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1538,7 +1538,7 @@ message ReferenceElement {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1551,8 +1551,8 @@ message ReferenceElement {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1647,7 +1647,7 @@ message Blob {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1660,8 +1660,8 @@ message Blob {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1777,7 +1777,7 @@ message File {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1790,8 +1790,8 @@ message File {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -1895,7 +1895,7 @@ message AnnotatedRelationshipElement {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -1908,8 +1908,8 @@ message AnnotatedRelationshipElement {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -2025,7 +2025,7 @@ message Entity {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -2038,8 +2038,8 @@ message Entity {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -2210,12 +2210,12 @@ message EventPayload {
   /// <summary>
   /// Reference to the source event element, including identification of
   /// <see cref="Aas.AssetAdministrationShell" />, <see cref="Aas.Submodel" />,
-  /// <see cref="Aas.SubmodelElement" />'s.
+  /// <see cref="Aas.SubmodelElement_choice" />'s.
   /// </summary>
   Reference source = 1;
 
   /// <summary>
-  /// <see cref="Aas.HasSemantics.semantic_id" /> of the source event element, if available
+  /// <see cref="Aas.HasSemantics_choice.semantic_id" /> of the source event element, if available
   /// </summary>
   /// <remarks>
   /// It is recommended to use a global reference.
@@ -2227,12 +2227,12 @@ message EventPayload {
   /// </summary>
   /// <remarks>
   /// Can be <see cref="Aas.AssetAdministrationShell" />, <see cref="Aas.Submodel" /> or
-  /// <see cref="Aas.SubmodelElement" />.
+  /// <see cref="Aas.SubmodelElement_choice" />.
   /// </remarks>
   Reference observable_reference = 3;
 
   /// <summary>
-  /// <see cref="Aas.HasSemantics.semantic_id" /> of the referable which defines the scope of
+  /// <see cref="Aas.HasSemantics_choice.semantic_id" /> of the referable which defines the scope of
   /// the event, if available.
   /// </summary>
   /// <remarks>
@@ -2286,7 +2286,7 @@ message BasicEventElement {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -2299,8 +2299,8 @@ message BasicEventElement {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -2370,9 +2370,9 @@ message BasicEventElement {
   repeated EmbeddedDataSpecification embedded_data_specifications = 9;
 
   /// <summary>
-  /// Reference to the <see cref="Aas.Referable" />, which defines the scope of the event.
+  /// Reference to the <see cref="Aas.Referable_choice" />, which defines the scope of the event.
   /// Can be <see cref="Aas.AssetAdministrationShell" />, <see cref="Aas.Submodel" />, or
-  /// <see cref="Aas.SubmodelElement" />.
+  /// <see cref="Aas.SubmodelElement_choice" />.
   /// </summary>
   /// <remarks>
   /// Reference to a referable, e.g., a data element or
@@ -2404,9 +2404,9 @@ message BasicEventElement {
 
   /// <summary>
   /// Information, which outer message infrastructure shall handle messages for
-  /// the <see cref="Aas.EventElement" />. Refers to a <see cref="Aas.Submodel" />,
+  /// the <see cref="Aas.EventElement_choice" />. Refers to a <see cref="Aas.Submodel" />,
   /// <see cref="Aas.SubmodelElementList" />, <see cref="Aas.SubmodelElementCollection" /> or
-  /// <see cref="Aas.Entity" />, which contains <see cref="Aas.DataElement" />'s describing
+  /// <see cref="Aas.Entity" />, which contains <see cref="Aas.DataElement_choice" />'s describing
   /// the proprietary specification for the message broker.
   /// </summary>
   /// <remarks>
@@ -2462,7 +2462,7 @@ message BasicEventElement {
 /// <ul>
 ///   <li>
 ///     Constraint AASd-134:
-///     For an <see cref="Aas.Operation" /> the <see cref="Aas.Referable.id_short" /> of all
+///     For an <see cref="Aas.Operation" /> the <see cref="Aas.Referable_choice.id_short" /> of all
 ///     <see cref="Aas.OperationVariable.value" />'s in
 ///     <see cref="Aas.Operation.input_variables" />, <see cref="Aas.Operation.output_variables" />
 ///     and <see cref="Aas.Operation.inoutput_variables" /> shall be unique.
@@ -2483,7 +2483,7 @@ message Operation {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -2496,8 +2496,8 @@ message Operation {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -2615,7 +2615,7 @@ message Capability {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -2628,8 +2628,8 @@ message Capability {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -2802,7 +2802,7 @@ message ConceptDescription {
   /// </summary>
   /// <remarks>
   /// The category is not identical to the semantic definition
-  /// (<see cref="Aas.HasSemantics" />) of an element. The category e.g. could denote that
+  /// (<see cref="Aas.HasSemantics_choice" />) of an element. The category e.g. could denote that
   /// the element is a measurement value whereas the semantic definition of
   /// the element would denote that it is the measured temperature.
   /// </remarks>
@@ -2815,8 +2815,8 @@ message ConceptDescription {
   /// </summary>
   /// <remarks>
   /// In case the element is a property and the property has a semantic definition
-  /// (<see cref="Aas.HasSemantics.semantic_id" />) conformant to IEC61360
-  /// the <see cref="Aas.Referable.id_short" /> is typically identical to the short name in English.
+  /// (<see cref="Aas.HasSemantics_choice.semantic_id" />) conformant to IEC61360
+  /// the <see cref="Aas.Referable_choice.id_short" /> is typically identical to the short name in English.
   /// </remarks>
   optional string id_short = 3;
 
@@ -3002,7 +3002,7 @@ message Reference {
   ReferenceTypes type = 1;
 
   /// <summary>
-  /// <see cref="Aas.HasSemantics.semantic_id" /> of the referenced model element
+  /// <see cref="Aas.HasSemantics_choice.semantic_id" /> of the referenced model element
   /// (<see cref="Aas.Reference.type" /> = <see cref="Aas.ReferenceTypes.MODEL_REFERENCE" />).
   /// </summary>
   /// <remarks>
@@ -3084,7 +3084,7 @@ enum KeyTypes {
   /// Event.
   /// </summary>
   /// <remarks>
-  /// <see cref="Aas.EventElement" /> is abstract.
+  /// <see cref="Aas.EventElement_choice" /> is abstract.
   /// </remarks>
   Keytypes_EVENT_ELEMENT = 9;
 
@@ -3232,7 +3232,7 @@ message LangStringNameType {
   string language = 1;
 
   /// <summary>
-  /// Text in the <see cref="Aas.AbstractLangString.language" />
+  /// Text in the <see cref="Aas.AbstractLangString_choice.language" />
   /// </summary>
   string text = 2;
 }
@@ -3247,7 +3247,7 @@ message LangStringTextType {
   string language = 1;
 
   /// <summary>
-  /// Text in the <see cref="Aas.AbstractLangString.language" />
+  /// Text in the <see cref="Aas.AbstractLangString_choice.language" />
   /// </summary>
   string text = 2;
 }
@@ -3282,14 +3282,14 @@ message Environment {
 /// </summary>
 message EmbeddedDataSpecification {
   /// <summary>
-  /// Reference to the data specification
+  /// Actual content of the data specification
   /// </summary>
-  Reference data_specification = 1;
+  DataSpecificationContent_choice data_specification_content = 1;
 
   /// <summary>
-  /// Actual content of the data specification
+  /// Reference to the data specification
   /// </summary>
-  DataSpecificationContent_choice data_specification_content = 2;
+  Reference data_specification = 2;
 }
 
 enum DataTypeIec61360 {
@@ -3559,7 +3559,7 @@ message LangStringPreferredNameTypeIec61360 {
   string language = 1;
 
   /// <summary>
-  /// Text in the <see cref="Aas.AbstractLangString.language" />
+  /// Text in the <see cref="Aas.AbstractLangString_choice.language" />
   /// </summary>
   string text = 2;
 }
@@ -3574,7 +3574,7 @@ message LangStringShortNameTypeIec61360 {
   string language = 1;
 
   /// <summary>
-  /// Text in the <see cref="Aas.AbstractLangString.language" />
+  /// Text in the <see cref="Aas.AbstractLangString_choice.language" />
   /// </summary>
   string text = 2;
 }
@@ -3589,7 +3589,7 @@ message LangStringDefinitionTypeIec61360 {
   string language = 1;
 
   /// <summary>
-  /// Text in the <see cref="Aas.AbstractLangString.language" />
+  /// Text in the <see cref="Aas.AbstractLangString_choice.language" />
   /// </summary>
   string text = 2;
 }
@@ -3603,7 +3603,7 @@ message LangStringDefinitionTypeIec61360 {
 /// IEC61360 requires also a globally unique identifier for a concept
 /// description. This ID is not part of the data specification template.
 /// Instead the <see cref="Aas.ConceptDescription.id" /> as inherited via
-/// <see cref="Aas.Identifiable" /> is used. Same holds for administrative
+/// <see cref="Aas.Identifiable_choice" /> is used. Same holds for administrative
 /// information like the version and revision.
 /// </para>
 /// <para>
diff --git a/test_data/proto/test_main/aas_core_meta.v3/input/snippets/package.txt b/test_data/proto/test_main/aas_core_meta.v3/input/snippets/package.txt
new file mode 100644
index 00000000..f448a2d7
--- /dev/null
+++ b/test_data/proto/test_main/aas_core_meta.v3/input/snippets/package.txt
@@ -0,0 +1 @@
+aas_core.aas3_0
diff --git a/test_data/proto/test_main/expected/abstract_and_concrete_classes/expected_output/stdout.txt b/test_data/proto/test_main/abstract_and_concrete_classes/expected_output/stdout.txt
similarity index 100%
rename from test_data/proto/test_main/expected/abstract_and_concrete_classes/expected_output/stdout.txt
rename to test_data/proto/test_main/abstract_and_concrete_classes/expected_output/stdout.txt
diff --git a/test_data/proto/test_main/expected/abstract_and_concrete_classes/expected_output/types.proto b/test_data/proto/test_main/abstract_and_concrete_classes/expected_output/types.proto
similarity index 100%
rename from test_data/proto/test_main/expected/abstract_and_concrete_classes/expected_output/types.proto
rename to test_data/proto/test_main/abstract_and_concrete_classes/expected_output/types.proto
diff --git a/test_data/proto/test_main/expected/abstract_and_concrete_classes/input/snippets/namespace.txt b/test_data/proto/test_main/abstract_and_concrete_classes/input/snippets/package.txt
similarity index 100%
rename from test_data/proto/test_main/expected/abstract_and_concrete_classes/input/snippets/namespace.txt
rename to test_data/proto/test_main/abstract_and_concrete_classes/input/snippets/package.txt
diff --git a/test_data/proto/test_main/expected/abstract_and_concrete_classes/meta_model.py b/test_data/proto/test_main/abstract_and_concrete_classes/meta_model.py
similarity index 100%
rename from test_data/proto/test_main/expected/abstract_and_concrete_classes/meta_model.py
rename to test_data/proto/test_main/abstract_and_concrete_classes/meta_model.py
diff --git a/test_data/proto/test_main/expected/concrete_class_with_descendants/expected_output/stdout.txt b/test_data/proto/test_main/concrete_class_with_descendants/expected_output/stdout.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_descendants/expected_output/stdout.txt
rename to test_data/proto/test_main/concrete_class_with_descendants/expected_output/stdout.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_descendants/expected_output/types.proto b/test_data/proto/test_main/concrete_class_with_descendants/expected_output/types.proto
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_descendants/expected_output/types.proto
rename to test_data/proto/test_main/concrete_class_with_descendants/expected_output/types.proto
diff --git a/test_data/proto/test_main/expected/concrete_class_with_descendants/input/snippets/namespace.txt b/test_data/proto/test_main/concrete_class_with_descendants/input/snippets/package.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_descendants/input/snippets/namespace.txt
rename to test_data/proto/test_main/concrete_class_with_descendants/input/snippets/package.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_descendants/meta_model.py b/test_data/proto/test_main/concrete_class_with_descendants/meta_model.py
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_descendants/meta_model.py
rename to test_data/proto/test_main/concrete_class_with_descendants/meta_model.py
diff --git a/test_data/proto/test_main/expected/concrete_class_with_enum/expected_output/stdout.txt b/test_data/proto/test_main/concrete_class_with_enum/expected_output/stdout.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_enum/expected_output/stdout.txt
rename to test_data/proto/test_main/concrete_class_with_enum/expected_output/stdout.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_enum/expected_output/types.proto b/test_data/proto/test_main/concrete_class_with_enum/expected_output/types.proto
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_enum/expected_output/types.proto
rename to test_data/proto/test_main/concrete_class_with_enum/expected_output/types.proto
diff --git a/test_data/proto/test_main/expected/concrete_class_with_enum/input/snippets/namespace.txt b/test_data/proto/test_main/concrete_class_with_enum/input/snippets/package.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_enum/input/snippets/namespace.txt
rename to test_data/proto/test_main/concrete_class_with_enum/input/snippets/package.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_enum/meta_model.py b/test_data/proto/test_main/concrete_class_with_enum/meta_model.py
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_enum/meta_model.py
rename to test_data/proto/test_main/concrete_class_with_enum/meta_model.py
diff --git a/test_data/proto/test_main/expected/concrete_class_with_list_of_instances/expected_output/stdout.txt b/test_data/proto/test_main/concrete_class_with_list_of_instances/expected_output/stdout.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_list_of_instances/expected_output/stdout.txt
rename to test_data/proto/test_main/concrete_class_with_list_of_instances/expected_output/stdout.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_list_of_instances/expected_output/types.proto b/test_data/proto/test_main/concrete_class_with_list_of_instances/expected_output/types.proto
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_list_of_instances/expected_output/types.proto
rename to test_data/proto/test_main/concrete_class_with_list_of_instances/expected_output/types.proto
diff --git a/test_data/proto/test_main/expected/concrete_class_with_list_of_instances/input/snippets/namespace.txt b/test_data/proto/test_main/concrete_class_with_list_of_instances/input/snippets/package.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_list_of_instances/input/snippets/namespace.txt
rename to test_data/proto/test_main/concrete_class_with_list_of_instances/input/snippets/package.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_list_of_instances/meta_model.py b/test_data/proto/test_main/concrete_class_with_list_of_instances/meta_model.py
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_list_of_instances/meta_model.py
rename to test_data/proto/test_main/concrete_class_with_list_of_instances/meta_model.py
diff --git a/test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/expected_output/stdout.txt b/test_data/proto/test_main/concrete_class_with_primitive_attributes/expected_output/stdout.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/expected_output/stdout.txt
rename to test_data/proto/test_main/concrete_class_with_primitive_attributes/expected_output/stdout.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/expected_output/types.proto b/test_data/proto/test_main/concrete_class_with_primitive_attributes/expected_output/types.proto
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/expected_output/types.proto
rename to test_data/proto/test_main/concrete_class_with_primitive_attributes/expected_output/types.proto
diff --git a/test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/input/snippets/namespace.txt b/test_data/proto/test_main/concrete_class_with_primitive_attributes/input/snippets/package.txt
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/input/snippets/namespace.txt
rename to test_data/proto/test_main/concrete_class_with_primitive_attributes/input/snippets/package.txt
diff --git a/test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/meta_model.py b/test_data/proto/test_main/concrete_class_with_primitive_attributes/meta_model.py
similarity index 100%
rename from test_data/proto/test_main/expected/concrete_class_with_primitive_attributes/meta_model.py
rename to test_data/proto/test_main/concrete_class_with_primitive_attributes/meta_model.py
diff --git a/test_data/proto/test_main/expected/aas_core_meta.v3/input/snippets/namespace.txt b/test_data/proto/test_main/expected/aas_core_meta.v3/input/snippets/namespace.txt
deleted file mode 100644
index 74a993a9..00000000
--- a/test_data/proto/test_main/expected/aas_core_meta.v3/input/snippets/namespace.txt
+++ /dev/null
@@ -1 +0,0 @@
-aas_core3
\ No newline at end of file

From b378f29b1623cedd37b44a744d0651f9c18dee20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Tue, 11 Mar 2025 07:54:15 +0100
Subject: [PATCH 3/7] improve protobuf file formatting

bring back the two new lines between protobuf package name and message definitions
---
 aas_core_codegen/protobuf/structure/_generate.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/aas_core_codegen/protobuf/structure/_generate.py b/aas_core_codegen/protobuf/structure/_generate.py
index 645101b3..13f27e0a 100644
--- a/aas_core_codegen/protobuf/structure/_generate.py
+++ b/aas_core_codegen/protobuf/structure/_generate.py
@@ -494,6 +494,7 @@ def generate(
 
 package {namespace};
 
+
 {code_blocks_joined}"""
         ),
         proto_common.WARNING,

From 67844a6bf3d0c6fc4c3ca6758db1b513e4f3b2c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Tue, 11 Mar 2025 08:00:31 +0100
Subject: [PATCH 4/7] update test to latest aas-core-meta

align the expected output of the protobuf generator with the latest version of aas-core-meta
---
 .../aas_core_meta.v3/expected_output/types.proto          | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto b/test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto
index 6a20f479..e7e5aa29 100644
--- a/test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto
+++ b/test_data/proto/test_main/aas_core_meta.v3/expected_output/types.proto
@@ -3282,14 +3282,14 @@ message Environment {
 /// </summary>
 message EmbeddedDataSpecification {
   /// <summary>
-  /// Actual content of the data specification
+  /// Reference to the data specification
   /// </summary>
-  DataSpecificationContent_choice data_specification_content = 1;
+  Reference data_specification = 1;
 
   /// <summary>
-  /// Reference to the data specification
+  /// Actual content of the data specification
   /// </summary>
-  Reference data_specification = 2;
+  DataSpecificationContent_choice data_specification_content = 2;
 }
 
 enum DataTypeIec61360 {

From 5bfcd1e7ab1ab5ea9b9a3ceec2bb20b33fb4ff3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Tue, 11 Mar 2025 08:04:51 +0100
Subject: [PATCH 5/7] apply code formatting checks

---
 aas_core_codegen/protobuf/description.py | 4 +++-
 aas_core_codegen/protobuf/naming.py      | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/aas_core_codegen/protobuf/description.py b/aas_core_codegen/protobuf/description.py
index c9256a24..06e22ff5 100644
--- a/aas_core_codegen/protobuf/description.py
+++ b/aas_core_codegen/protobuf/description.py
@@ -227,7 +227,9 @@ def transform_reference_to_attribute_in_doc(
             if isinstance(element.reference.cls, intermediate.AbstractClass):
                 # We do not generate ProtoBuf code for abstract classes, so we have to refer
                 # to the interface.
-                name_of_our_type = proto_naming.interface_name(element.reference.cls.name)
+                name_of_our_type = proto_naming.interface_name(
+                    element.reference.cls.name
+                )
             elif isinstance(element.reference.cls, intermediate.ConcreteClass):
                 # NOTE (mristin, 2021-12-25):
                 # Though a concrete class can have multiple descendants and the writer
diff --git a/aas_core_codegen/protobuf/naming.py b/aas_core_codegen/protobuf/naming.py
index 189e2578..a6addd1e 100644
--- a/aas_core_codegen/protobuf/naming.py
+++ b/aas_core_codegen/protobuf/naming.py
@@ -16,7 +16,9 @@ def interface_name(identifier: Identifier) -> Identifier:
     Since proto3 does not directly support interfaces, but only one-of messages
     (commonly suffixed "_choice"), these names are generated here.
     """
-    return aas_core_codegen.naming.capitalized_camel_case(identifier) + "_choice"
+    return Identifier(
+        aas_core_codegen.naming.capitalized_camel_case(identifier) + "_choice"
+    )
 
 
 def enum_name(identifier: Identifier) -> Identifier:

From 98b48acd68998c687e85f5eda5042285a2a0028b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Tue, 11 Mar 2025 08:36:29 +0100
Subject: [PATCH 6/7] fix test setup for protobuf generator

---
 dev_scripts/run_tests_with_rerecord.py | 1 +
 tests/proto/test_main.py               | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/dev_scripts/run_tests_with_rerecord.py b/dev_scripts/run_tests_with_rerecord.py
index 366aac06..3252ed32 100644
--- a/dev_scripts/run_tests_with_rerecord.py
+++ b/dev_scripts/run_tests_with_rerecord.py
@@ -24,6 +24,7 @@ def main() -> int:
         "tests.smoke.test_main.Test_against_recorded",
         "tests.typescript.test_main.Test_against_recorded",
         "tests.xsd.test_main.Test_against_recorded",
+        "tests.proto.test_main.Test_against_recorded",
     ]
 
     parser = argparse.ArgumentParser(description=__doc__)
diff --git a/tests/proto/test_main.py b/tests/proto/test_main.py
index f6f0d3b7..8736a4c5 100644
--- a/tests/proto/test_main.py
+++ b/tests/proto/test_main.py
@@ -18,7 +18,7 @@
 
 class Test_against_recorded(unittest.TestCase):
     def test_against_expected_meta_models(self) -> None:
-        parent_case_dir = REPO_DIR / "test_data" / "proto" / "test_main" / "expected"
+        parent_case_dir = REPO_DIR / "test_data" / "proto" / "test_main"
         assert parent_case_dir.exists() and parent_case_dir.is_dir(), parent_case_dir
 
         # fmt: off

From 7c16e68a48df8056af3dd92ca8fed6b046b1bba6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=20Gneu=C3=9F?= <tom.gneuss@tu-dresden.de>
Date: Tue, 11 Mar 2025 09:14:39 +0100
Subject: [PATCH 7/7] fix pylint warnings

---
 aas_core_codegen/protobuf/common.py | 2 +-
 aas_core_codegen/protobuf/naming.py | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/aas_core_codegen/protobuf/common.py b/aas_core_codegen/protobuf/common.py
index 4afdeeef..e2a4b25a 100644
--- a/aas_core_codegen/protobuf/common.py
+++ b/aas_core_codegen/protobuf/common.py
@@ -6,7 +6,7 @@
 from icontract import ensure, require
 
 from aas_core_codegen import intermediate
-from aas_core_codegen.common import Stripped, assert_never, Identifier
+from aas_core_codegen.common import Stripped, assert_never
 from aas_core_codegen.protobuf import naming as proto_naming
 
 
diff --git a/aas_core_codegen/protobuf/naming.py b/aas_core_codegen/protobuf/naming.py
index a6addd1e..8ca011ee 100644
--- a/aas_core_codegen/protobuf/naming.py
+++ b/aas_core_codegen/protobuf/naming.py
@@ -2,8 +2,6 @@
 
 from typing import Union
 
-from icontract import ensure
-
 import aas_core_codegen.naming
 from aas_core_codegen import intermediate
 from aas_core_codegen.common import Identifier, assert_never