Adding topic inheritance test

.azure/templates/build-test.yml

@@ -34,6 +34,7 @@ steps:
       set -e -x
       python -m pip install --user --upgrade pip wheel setuptools
       python -m pip install --user --upgrade pytest-azurepipelines
+      python -m pip install --user --upgrade pytest-asyncio
       python -m pip install --user .[dev]
     name: install_cyclonedds_py
     displayName: Run installers

tests/test_topic_inheritance.py

@@ -0,0 +1,91 @@
+import asyncio
+import pytest
+
+import cyclonedds.idl as idl
+import cyclonedds.idl.annotations as annotate
+
+from dataclasses import dataclass
+from cyclonedds.domain import DomainParticipant
+from cyclonedds.topic import Topic
+from cyclonedds.pub import DataWriter
+from cyclonedds.sub import DataReader
+from cyclonedds.util import duration
+
+
+@dataclass
+@annotate.mutable
+@annotate.autoid("sequential")
+class Base(idl.IdlStruct, typename="Hierarchy.Base"):
+    fieldA: str
+
+
+@dataclass
+@annotate.mutable
+@annotate.autoid("sequential")
+class Derived(Base, typename="Hierarchy.Derived"):
+    fieldB: str
+
+
+@pytest.mark.asyncio
+async def test_base_topic():
+    '''
+    Creates a publisher and a subscriber of the Base topic and checks if the
+    update sent by the publisher is received by the subscriber.
+    '''
+    base = Base(fieldA='Lorem')
+    tasks = [
+        _subscriber(Base),
+        _publisher(Base, base),
+    ]
+    results = await asyncio.gather(*tasks)
+    assert results[0] == results[1]
+
+
+@pytest.mark.asyncio
+async def test_derived_topic():
+    '''
+    Creates a publisher and a subscriber of the Derived topic and checks if the
+    update sent by the publisher is received by the subscriber.
+    '''
+    #base = Base(fieldA='Lorem')
+    derived = Derived(
+        fieldA='Ipsum',
+        fieldB='Dolor')
+
+    tasks = [
+        # This should not be necessary. I suspect there is a bug in CycloneDDS
+        #_subscriber(Base),
+        #_publisher(Base, base),
+
+        # This is the part of the test that really matters
+        _subscriber(Derived),
+        _publisher(Derived, derived),
+    ]
+
+    results = await asyncio.gather(*tasks)
+    assert results[0] == results[1]
+    # assert results[2] == results[3]
+
+
+async def _publisher(topicClass, value, timeout=2):
+    '''
+    Sends a given value.
+    '''
+    participant = DomainParticipant(0)
+    topic = Topic(participant, topicClass.__name__, topicClass)
+    writer = DataWriter(participant, topic)
+    writer.write(value)
+    await asyncio.sleep(timeout)
+    return value
+
+
+async def _subscriber(topicClass, timeout=2):
+    '''
+    Receives an update. Returns None if no update is not received within a
+    given timeout.
+    '''
+    participant = DomainParticipant(0)
+    topic = Topic(participant, topicClass.__name__, topicClass)
+    reader = DataReader(participant, topic)
+    async for update in reader.read_aiter(timeout=duration(seconds=timeout)):
+        return update