diff --git a/rosidl_parser/rosidl_parser/idl_to_message_spec.py b/rosidl_parser/rosidl_parser/idl_to_message_spec.py
new file mode 100644
index 000000000..376cfc156
--- /dev/null
+++ b/rosidl_parser/rosidl_parser/idl_to_message_spec.py
@@ -0,0 +1,157 @@
+from pathlib import Path
+from types import NoneType
+from typing import Any, List, Type
+
+from ament_index_python.packages import get_package_share_directory
+
+from rosidl_parser.parser import parse_idl_file
+import rosidl_parser.definition as idl_def
+import rosidl_adapter.parser as rosidl_parser
+from rosidl_adapter.msg import MSG_TYPE_TO_IDL
+
+IDL_TYPE_TO_MSG = {v: k for k, v in MSG_TYPE_TO_IDL.items()}
+
+BOUNDED_TYPES = [idl_def.BoundedSequence, idl_def.Array]
+BRACKET_TYPES = BOUNDED_TYPES + [idl_def.UnboundedSequence, idl_def.Array]
+STRING_BOUND_TYPES = [idl_def.BoundedString, idl_def.BoundedWString]
+
+UNSUPPORTED_ROSIDL_TYPES = {
+    'long double': 'float64'
+}
+
+
+def find_value(haystack: List, name: str) -> Any:
+    for a in haystack:
+        if a.name == name:
+            return a.value
+
+    return None
+
+
+def find_annotation_value(annotations: List, name: str, value_key="value") -> Any:
+    for a in annotations:
+        if a.name == name:
+            return a.value[value_key]
+
+    return None
+
+
+def resolve_typename(member_type: Type[idl_def.AbstractType]) -> str:
+    if isinstance(member_type, idl_def.BasicType):
+        return member_type.typename
+    elif isinstance(member_type, idl_def.AbstractWString):
+        return "wstring"
+    elif isinstance(member_type, idl_def.AbstractString):
+        return "string"
+    elif isinstance(member_type, idl_def.NamedType):
+        return member_type.name
+    elif isinstance(member_type, idl_def.AbstractNestedType):
+        return resolve_typename(member_type.value_type)
+    else:
+        return member_type.name
+
+
+def build_type_string(member_type: Type[idl_def.AbstractType], constants: List[idl_def.Constant]) -> str:
+    type_string = resolve_typename(member_type)
+
+    if type_string in IDL_TYPE_TO_MSG:
+        type_string = IDL_TYPE_TO_MSG[type_string]
+    elif type_string in UNSUPPORTED_ROSIDL_TYPES:
+        print(f"WARNING: Unsupported type could result in in loss of precision '{type_string}' --> '{UNSUPPORTED_ROSIDL_TYPES[type_string]}'")
+        type_string = UNSUPPORTED_ROSIDL_TYPES[type_string]
+
+    has_string_bounds = any(isinstance(member_type, t) for t in STRING_BOUND_TYPES)
+    string_upper_bound = member_type.maximum_size if has_string_bounds else None
+    has_brackets = any(isinstance(member_type, t) for t in BRACKET_TYPES)
+
+    if type_string == 'wchar':
+        # hack to support wchar as a wstring with length 1
+        type_string = 'wstring'
+        has_string_bounds = True
+        string_upper_bound = 1
+
+    if has_string_bounds:
+        if type(string_upper_bound) == str:
+            # constant bounded type needs to be resolved to the value
+            string_upper_bound = find_value(constants, string_upper_bound)
+            assert string_upper_bound is not None
+
+        type_string += f"{rosidl_parser.STRING_UPPER_BOUND_TOKEN}{string_upper_bound}"
+
+    if has_brackets:
+        bounds = ''
+        if isinstance(member_type, idl_def.BoundedSequence):
+            bounds = f"{rosidl_parser.ARRAY_UPPER_BOUND_TOKEN}{member_type.maximum_size}"
+        if isinstance(member_type, idl_def.Array):
+            bounds = f"{member_type.size}"
+        type_string += f"[{bounds}]"
+
+    return type_string
+
+
+def process_constants(constants: List[idl_def.Constant]) -> List[rosidl_parser.Constant]:
+    out_constants = []
+    for c in constants:
+        if isinstance(c.type, idl_def.BoundedString):
+            typename = "string"
+        elif isinstance(c.type, idl_def.BoundedWString):
+            typename = "wstring"
+        else:
+            typename = IDL_TYPE_TO_MSG[c.type.typename]
+        out_constants.append(rosidl_parser.Constant(typename, c.name, str(c.value)))
+    return out_constants
+
+
+def process_members(members: List[idl_def.Member], constants: List[idl_def.Constant]) -> List[rosidl_parser.Field]:
+    fields = []
+    for m in members:
+        type_pkg_name = None
+        type_string = build_type_string(m.type, constants)
+
+        if isinstance(m.type, idl_def.NamespacedType):
+            type_pkg_name = m.type.namespaces[0]
+
+        field_type = rosidl_parser.Type(type_string, type_pkg_name)
+
+        default_value_str = find_annotation_value(m.annotations, 'default')
+        if type(default_value_str) not in [NoneType, str]:
+            default_value_str = str(default_value_str)
+
+        fields.append(rosidl_parser.Field(field_type, m.name, default_value_str))
+
+    return fields
+
+
+def parse_idl_message(pkg_name: str, msg_name: str, idl_msg: idl_def.Message) -> rosidl_parser.MessageSpecification:
+    fields = process_members(idl_msg.structure.members, idl_msg.constants)
+    constants = process_constants(idl_msg.constants)
+
+    msg = rosidl_parser.MessageSpecification(pkg_name, msg_name, fields, constants)
+    # TODO add comments
+    # msg.annotations['comment'] = message_comments
+
+    return msg
+
+
+def parse_idl_to_message_spec(pkg_name: str, interface_file_path: str) -> rosidl_parser.MessageSpecification:
+    path = Path(interface_file_path)
+    # share_dir = get_package_share_directory(pkg_name)
+    share_dir = path.parent
+    msg_name = path.stem
+
+    idl_file = parse_idl_file(idl_def.IdlLocator(share_dir, path.relative_to(share_dir)))
+    idl_msg = idl_file.content.get_elements_of_type(idl_def.Message)[0]
+    return parse_idl_message(pkg_name, msg_name, idl_msg)
+
+
+def parse_idl_to_service_spec(pkg_name: str, interface_file_path: str) -> rosidl_parser.ServiceSpecification:
+    path = Path(interface_file_path)
+    share_dir = get_package_share_directory(pkg_name)
+    srv_name = path.stem
+
+    idl_file = parse_idl_file(idl_def.IdlLocator(share_dir, path.relative_to(share_dir)))
+    idl_srv = idl_file.content.get_elements_of_type(idl_def.Service)[0]
+    request_message = parse_idl_message(pkg_name, srv_name + rosidl_parser.SERVICE_REQUEST_MESSAGE_SUFFIX, idl_srv.request_message)
+    response_message = parse_idl_message(pkg_name, srv_name + rosidl_parser.SERVICE_RESPONSE_MESSAGE_SUFFIX, idl_srv.response_message)
+
+    return rosidl_parser.ServiceSpecification(pkg_name, srv_name, request_message, response_message)
diff --git a/rosidl_parser/test/msg/MyMessage.msg b/rosidl_parser/test/msg/MyMessage.msg
new file mode 100644
index 000000000..6f3bd1ba1
--- /dev/null
+++ b/rosidl_parser/test/msg/MyMessage.msg
@@ -0,0 +1,53 @@
+# tmp_msgs/MyMessage
+int16 SHORT_CONSTANT=-23
+uint32 UNSIGNED_LONG_CONSTANT=42
+float32 FLOAT_CONSTANT=1.25
+bool BOOLEAN_CONSTANT=True
+string STRING_CONSTANT='string_value'
+wstring WSTRING_CONSTANT='wstring_value_\u2122'
+string EMPTY_STRING_CONSTANT=''
+int16 short_value
+int16 short_value2
+uint16 unsigned_short_value 123
+int32 long_value
+uint32 unsigned_long_value
+int64 long_long_value
+uint64 unsigned_long_long_value
+float32 float_value
+float64 double_value
+float64 long_double_value
+char char_value
+wstring<=1 wchar_value
+bool boolean_value
+byte octet_value
+int8 int8_value
+uint8 uint8_value
+int16 int16_value
+uint16 uint16_value
+int32 int32_value
+uint32 uint32_value
+int64 int64_value
+uint64 uint64_value
+string string_value
+string<=5 bounded_string_value
+wstring wstring_value
+wstring<=23 bounded_wstring_value
+wstring<=42 constant_bounded_wstring_value
+int16[] unbounded_short_values
+int16[<=5] bounded_short_values
+string[] unbounded_values_of_bounded_strings
+string[<=4] bounded_values_of_bounded_strings
+int16[23] array_short_values
+float32 int_and_frac_with_positive_scientific 19000000000.0
+float32 int_and_frac_with_explicit_positive_scientific 19000000000.0
+float32 int_and_frac_with_negative_scientific 1.1e-10
+float32 int_and_frac 9e-05
+float32 int_with_empty_frac 1.0
+float32 frac_only 0.1
+float32 int_with_positive_scientific 900000.0
+float32 int_with_explicit_positive_scientific 900000.0
+float32 int_with_negative_scientific 9e-05
+float32 fixed_int_and_frac 8.7
+float32 fixed_int_with_dot_only 4.0
+float32 fixed_frac_only 0.3
+float32 fixed_int_only 7.0
\ No newline at end of file
diff --git a/rosidl_parser/test/test_msg_spec_translate.py b/rosidl_parser/test/test_msg_spec_translate.py
new file mode 100644
index 000000000..0c2bc995f
--- /dev/null
+++ b/rosidl_parser/test/test_msg_spec_translate.py
@@ -0,0 +1,418 @@
+# Copyright 2022 Open Source Robotics Foundation, Inc.
+#
+# 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.
+
+import pathlib
+
+import pytest
+
+from rosidl_parser.idl_to_message_spec import parse_idl_to_message_spec, parse_idl_to_service_spec
+
+MESSAGE_IDL_PATH = pathlib.Path(__file__).parent / pathlib.Path('msg') / 'MyMessage.idl'
+MESSAGE_ROSIDL_PATH = pathlib.Path(__file__).parent / pathlib.Path('msg') / 'MyMessage.msg'
+
+# SERVICE_IDL_LOCATOR = IdlLocator(
+#     pathlib.Path(__file__).parent, pathlib.Path('srv') / 'MyService.idl')
+# ACTION_IDL_LOCATOR = IdlLocator(
+#     pathlib.Path(__file__).parent, pathlib.Path('action') / 'MyAction.idl')
+
+
+@pytest.fixture(scope='module')
+def rosidl_msg_spec():
+    return parse_idl_to_message_spec('tmp_msgs', MESSAGE_IDL_PATH)
+
+
+def test_idl_to_rosidl_translation(rosidl_msg_spec):
+    assert str(rosidl_msg_spec) == MESSAGE_ROSIDL_PATH.read_text()
+
+
+# def test_message_parser_structure(message_rosidl_file):
+#     messages = message_idl_file.content.get_elements_of_type(Message)
+#     assert len(messages) == 1
+#
+#     constants = messages[0].constants
+#     assert len(constants) == 7
+#
+#     assert constants[0].name == 'SHORT_CONSTANT'
+#     assert isinstance(constants[0].type, BasicType)
+#     assert constants[0].type.typename == 'int16'
+#     assert constants[0].value == -23
+#
+#     assert constants[1].name == 'UNSIGNED_LONG_CONSTANT'
+#     assert isinstance(constants[1].type, BasicType)
+#     assert constants[1].type.typename == 'uint32'
+#     assert constants[1].value == 42
+#
+#     assert constants[2].name == 'FLOAT_CONSTANT'
+#     assert isinstance(constants[2].type, BasicType)
+#     assert constants[2].type.typename == 'float'
+#     assert constants[2].value == 1.25
+#
+#     assert constants[3].name == 'BOOLEAN_CONSTANT'
+#     assert isinstance(constants[3].type, BasicType)
+#     assert constants[3].type.typename == 'boolean'
+#     assert constants[3].value is True
+#
+#     assert constants[4].name == 'STRING_CONSTANT'
+#     assert isinstance(constants[4].type, BoundedString)
+#     assert constants[4].value == 'string_value'
+#
+#     assert constants[5].name == 'WSTRING_CONSTANT'
+#     assert isinstance(constants[5].type, BoundedWString)
+#     assert constants[5].value == 'wstring_value_\\u2122'
+#
+#     assert constants[6].name == 'EMPTY_STRING_CONSTANT'
+#     assert isinstance(constants[6].type, BoundedString)
+#     assert constants[6].value == ''
+#
+#     structure = messages[0].structure
+#     assert structure.namespaced_type.namespaces == ['rosidl_parser', 'msg']
+#     assert structure.namespaced_type.name == 'MyMessage'
+#     assert len(structure.members) == 45
+#
+#     assert isinstance(structure.members[0].type, BasicType)
+#     assert structure.members[0].type.typename == 'int16'
+#     assert structure.members[0].name == 'short_value'
+#     assert isinstance(structure.members[1].type, BasicType)
+#     assert structure.members[1].type.typename == 'int16'
+#     assert structure.members[1].name == 'short_value2'
+#
+#     assert isinstance(structure.members[22].type, UnboundedString)
+#     assert structure.members[22].name == 'string_value'
+#     assert isinstance(structure.members[23].type, BoundedString)
+#     assert structure.members[23].type.maximum_size == 5
+#     assert structure.members[23].name == 'bounded_string_value'
+#
+#     assert isinstance(structure.members[24].type, UnboundedWString)
+#     assert structure.members[24].name == 'wstring_value'
+#     assert isinstance(structure.members[25].type, BoundedWString)
+#     assert structure.members[25].type.maximum_size == 23
+#     assert structure.members[25].name == 'bounded_wstring_value'
+#     assert isinstance(structure.members[26].type, BoundedWString)
+#     assert structure.members[26].type.maximum_size == 'UNSIGNED_LONG_CONSTANT'
+#     assert structure.members[26].name == 'constant_bounded_wstring_value'
+#
+#     assert isinstance(structure.members[27].type, UnboundedSequence)
+#     assert isinstance(structure.members[27].type.value_type, BasicType)
+#     assert structure.members[27].type.value_type.typename == 'int16'
+#     assert structure.members[27].name == 'unbounded_short_values'
+#     assert isinstance(structure.members[28].type, BoundedSequence)
+#     assert isinstance(structure.members[28].type.value_type, BasicType)
+#     assert structure.members[28].type.value_type.typename == 'int16'
+#     assert structure.members[28].type.maximum_size == 5
+#     assert structure.members[28].name == 'bounded_short_values'
+#
+#     assert isinstance(structure.members[29].type, UnboundedSequence)
+#     assert isinstance(structure.members[29].type.value_type, BoundedString)
+#     assert structure.members[29].type.value_type.maximum_size == 3
+#     assert structure.members[29].name == 'unbounded_values_of_bounded_strings'
+#
+#     assert isinstance(structure.members[30].type, BoundedSequence)
+#     assert isinstance(structure.members[30].type.value_type, BoundedString)
+#     assert structure.members[30].type.value_type.maximum_size == 3
+#     assert structure.members[30].type.maximum_size == 4
+#     assert structure.members[30].name == 'bounded_values_of_bounded_strings'
+#
+#     assert isinstance(structure.members[31].type, Array)
+#     assert isinstance(structure.members[31].type.value_type, BasicType)
+#     assert structure.members[31].type.value_type.typename == 'int16'
+#     assert structure.members[31].type.size == 23
+#     assert structure.members[31].name == 'array_short_values'
+#
+#
+# def test_message_parser_annotations(message_idl_file):
+#     messages = message_idl_file.content.get_elements_of_type(Message)
+#     assert len(messages) == 1
+#     structure = messages[0].structure
+#
+#     assert len(structure.annotations) == 2
+#     assert structure.annotations[0].name == 'verbatim'
+#     assert len(structure.annotations[0].value) == 2
+#     assert 'language' in structure.annotations[0].value
+#     assert structure.annotations[0].value['language'] == 'comment'
+#     assert 'text' in structure.annotations[0].value
+#     assert structure.annotations[0].value['text'] == \
+#         'Documentation of MyMessage.Adjacent string literal.'
+#
+#     assert structure.annotations[1].name == 'transfer_mode'
+#     assert structure.annotations[1].value == 'SHMEM_REF'
+#
+#     assert len(structure.members[2].annotations) == 1
+#
+#     assert structure.members[2].annotations[0].name == 'default'
+#     assert len(structure.members[2].annotations[0].value) == 1
+#     assert 'value' in structure.members[2].annotations[0].value
+#     assert structure.members[2].annotations[0].value['value'] == 123
+#
+#     assert len(structure.members[3].annotations) == 2
+#
+#     assert structure.members[3].annotations[0].name == 'key'
+#     assert structure.members[3].annotations[0].value is None
+#
+#     assert structure.members[3].annotations[1].name == 'range'
+#     assert len(structure.members[3].annotations[1].value) == 2
+#     assert 'min' in structure.members[3].annotations[1].value
+#     assert structure.members[3].annotations[1].value['min'] == -10
+#     assert 'max' in structure.members[3].annotations[1].value
+#     assert structure.members[3].annotations[1].value['max'] == 10
+#
+#     assert isinstance(structure.members[32].type, BasicType)
+#     assert structure.members[32].type.typename == 'float'
+#     assert structure.members[32].name == 'int_and_frac_with_positive_scientific'
+#     assert len(structure.members[32].annotations) == 1
+#     assert structure.members[32].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[33].type, BasicType)
+#     assert structure.members[33].type.typename == 'float'
+#     assert structure.members[33].name == 'int_and_frac_with_explicit_positive_scientific'
+#     assert len(structure.members[33].annotations) == 1
+#     assert structure.members[33].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[34].type, BasicType)
+#     assert structure.members[34].type.typename == 'float'
+#     assert structure.members[34].name == 'int_and_frac_with_negative_scientific'
+#     assert len(structure.members[34].annotations) == 1
+#     assert structure.members[34].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[35].type, BasicType)
+#     assert structure.members[35].type.typename == 'float'
+#     assert structure.members[35].name == 'int_and_frac'
+#     assert len(structure.members[35].annotations) == 1
+#     assert structure.members[35].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[36].type, BasicType)
+#     assert structure.members[36].type.typename == 'float'
+#     assert structure.members[36].name == 'int_with_empty_frac'
+#     assert len(structure.members[36].annotations) == 1
+#     assert structure.members[36].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[37].type, BasicType)
+#     assert structure.members[37].type.typename == 'float'
+#     assert structure.members[37].name == 'frac_only'
+#     assert len(structure.members[37].annotations) == 1
+#     assert structure.members[37].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[38].type, BasicType)
+#     assert structure.members[38].type.typename == 'float'
+#     assert structure.members[38].name == 'int_with_positive_scientific'
+#     assert len(structure.members[38].annotations) == 1
+#     assert structure.members[38].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[39].type, BasicType)
+#     assert structure.members[39].type.typename == 'float'
+#     assert structure.members[39].name == 'int_with_explicit_positive_scientific'
+#     assert len(structure.members[39].annotations) == 1
+#     assert structure.members[39].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[40].type, BasicType)
+#     assert structure.members[40].type.typename == 'float'
+#     assert structure.members[40].name == 'int_with_negative_scientific'
+#     assert len(structure.members[40].annotations) == 1
+#     assert structure.members[40].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[41].type, BasicType)
+#     assert structure.members[41].type.typename == 'float'
+#     assert structure.members[41].name == 'fixed_int_and_frac'
+#     assert len(structure.members[41].annotations) == 1
+#     assert structure.members[41].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[42].type, BasicType)
+#     assert structure.members[42].type.typename == 'float'
+#     assert structure.members[42].name == 'fixed_int_with_dot_only'
+#     assert len(structure.members[42].annotations) == 1
+#     assert structure.members[42].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[43].type, BasicType)
+#     assert structure.members[43].type.typename == 'float'
+#     assert structure.members[43].name == 'fixed_frac_only'
+#     assert len(structure.members[43].annotations) == 1
+#     assert structure.members[43].annotations[0].name == 'default'
+#
+#     assert isinstance(structure.members[44].type, BasicType)
+#     assert structure.members[44].type.typename == 'float'
+#     assert structure.members[44].name == 'fixed_int_only'
+#     assert len(structure.members[44].annotations) == 1
+#     assert structure.members[44].annotations[0].name == 'default'
+
+
+# @pytest.fixture(scope='module')
+# def service_rosidl_file():
+#     return parse_idl_to_service_spec('tmp_msgs', SERVICE_IDL_PATH)
+
+
+# def test_service_parser(service_rosidl_file):
+#     services = service_idl_file.content.get_elements_of_type(Service)
+#     assert len(services) == 1
+#
+#     srv = services[0]
+#     assert isinstance(srv, Service)
+#     assert srv.namespaced_type.namespaces == ['rosidl_parser', 'srv']
+#     assert srv.namespaced_type.name == 'MyService'
+#     assert len(srv.request_message.structure.members) == 2
+#     assert len(srv.response_message.structure.members) == 1
+#
+#     constants = srv.request_message.constants
+#     assert len(constants) == 1
+#
+#     assert constants[0].name == 'SHORT_CONSTANT'
+#     assert isinstance(constants[0].type, BasicType)
+#     assert constants[0].type.typename == 'int16'
+#     assert constants[0].value == -23
+#
+#     constants = srv.response_message.constants
+#     assert len(constants) == 1
+#
+#     assert constants[0].name == 'UNSIGNED_LONG_CONSTANT'
+#     assert isinstance(constants[0].type, BasicType)
+#     assert constants[0].type.typename == 'uint32'
+#     assert constants[0].value == 42
+#
+#
+# @pytest.fixture(scope='module')
+# def action_idl_file():
+#     return parse_idl_file(ACTION_IDL_LOCATOR)
+#
+#
+# def test_action_parser(action_idl_file):
+#     actions = action_idl_file.content.get_elements_of_type(Action)
+#     assert len(actions) == 1
+#
+#     action = actions[0]
+#     assert isinstance(action, Action)
+#     assert action.namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert action.namespaced_type.name == 'MyAction'
+#
+#     # check messages defined in the idl file
+#     constants = action.goal.constants
+#     assert len(constants) == 1
+#     assert constants[0].name == 'SHORT_CONSTANT'
+#     assert isinstance(constants[0].type, BasicType)
+#     assert constants[0].type.typename == 'int16'
+#     assert constants[0].value == -23
+#
+#     structure = action.goal.structure
+#     assert structure.namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert structure.namespaced_type.name == 'MyAction_Goal'
+#     assert len(structure.members) == 1
+#     assert isinstance(structure.members[0].type, BasicType)
+#     assert structure.members[0].type.typename == 'int32'
+#     assert structure.members[0].name == 'input_value'
+#
+#     constants = action.result.constants
+#     assert len(constants) == 1
+#     assert constants[0].name == 'UNSIGNED_LONG_CONSTANT'
+#     assert isinstance(constants[0].type, BasicType)
+#     assert constants[0].type.typename == 'uint32'
+#     assert constants[0].value == 42
+#
+#     structure = action.result.structure
+#     assert structure.namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert structure.namespaced_type.name == 'MyAction_Result'
+#     assert len(structure.members) == 1
+#     assert isinstance(structure.members[0].type, BasicType)
+#     assert structure.members[0].type.typename == 'uint32'
+#     assert structure.members[0].name == 'output_value'
+#
+#     constants = action.feedback.constants
+#     assert len(constants) == 1
+#     assert constants[0].name == 'FLOAT_CONSTANT'
+#     assert isinstance(constants[0].type, BasicType)
+#     assert constants[0].type.typename == 'float'
+#     assert constants[0].value == 1.25
+#
+#     structure = action.feedback.structure
+#     assert structure.namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert structure.namespaced_type.name == 'MyAction_Feedback'
+#     assert len(structure.members) == 1
+#     assert isinstance(structure.members[0].type, BasicType)
+#     assert structure.members[0].type.typename == 'float'
+#     assert structure.members[0].name == 'progress_value'
+#
+#     # check derived goal service
+#     namespaced_type = action.send_goal_service.namespaced_type
+#     assert namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert namespaced_type.name == 'MyAction_SendGoal'
+#
+#     structure = action.send_goal_service.request_message.structure
+#     assert len(structure.members) == 2
+#
+#     assert isinstance(structure.members[0].type, NamespacedType)
+#     assert structure.members[0].type.namespaces == [
+#         'unique_identifier_msgs', 'msg']
+#     assert structure.members[0].type.name == 'UUID'
+#     assert structure.members[0].name == 'goal_id'
+#
+#     assert isinstance(structure.members[1].type, NamespacedType)
+#     assert structure.members[1].type.namespaces == \
+#         action.goal.structure.namespaced_type.namespaces
+#     assert structure.members[1].type.name == \
+#         action.goal.structure.namespaced_type.name
+#
+#     structure = action.send_goal_service.response_message.structure
+#     assert len(structure.members) == 2
+#
+#     assert isinstance(structure.members[0].type, BasicType)
+#     assert structure.members[0].type.typename == 'boolean'
+#     assert structure.members[0].name == 'accepted'
+#
+#     assert isinstance(structure.members[1].type, NamespacedType)
+#     assert structure.members[1].type.namespaces == [
+#         'builtin_interfaces', 'msg']
+#     assert structure.members[1].type.name == 'Time'
+#     assert structure.members[1].name == 'stamp'
+#
+#     # check derived result service
+#     namespaced_type = action.get_result_service.namespaced_type
+#     assert namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert namespaced_type.name == 'MyAction_GetResult'
+#
+#     structure = action.get_result_service.request_message.structure
+#     assert len(structure.members) == 1
+#
+#     assert isinstance(structure.members[0].type, NamespacedType)
+#     assert structure.members[0].type.namespaces == [
+#         'unique_identifier_msgs', 'msg']
+#     assert structure.members[0].type.name == 'UUID'
+#     assert structure.members[0].name == 'goal_id'
+#
+#     structure = action.get_result_service.response_message.structure
+#     assert len(structure.members) == 2
+#
+#     assert isinstance(structure.members[0].type, BasicType)
+#     assert structure.members[0].type.typename == 'int8'
+#     assert structure.members[0].name == 'status'
+#
+#     assert isinstance(structure.members[1].type, NamespacedType)
+#     assert structure.members[1].type.namespaces == \
+#         action.result.structure.namespaced_type.namespaces
+#     assert structure.members[1].type.name == \
+#         action.result.structure.namespaced_type.name
+#
+#     # check derived feedback message
+#     structure = action.feedback_message.structure
+#     assert structure.namespaced_type.namespaces == ['rosidl_parser', 'action']
+#     assert structure.namespaced_type.name == 'MyAction_FeedbackMessage'
+#
+#     assert len(structure.members) == 2
+#
+#     assert isinstance(structure.members[0].type, NamespacedType)
+#     assert structure.members[0].type.namespaces == [
+#         'unique_identifier_msgs', 'msg']
+#     assert structure.members[0].type.name == 'UUID'
+#     assert structure.members[0].name == 'goal_id'
+#
+#     assert isinstance(structure.members[1].type, NamespacedType)
+#     assert structure.members[1].type.namespaces == \
+#         action.feedback.structure.namespaced_type.namespaces
+#     assert structure.members[1].type.name == \
+#         action.feedback.structure.namespaced_type.name