tests (unit): Add tests for pubsub contacts:

Tests the models and plugin data behaviour.

rel 475

tests/unit/frontends/test_webrtc.py

@@ -28,7 +28,13 @@ from pytest_twisted import ensureDeferred as ed
 
 from libervia.backend.core import exceptions
 from libervia.backend.tools.common import data_format
-from libervia.frontends.tools import webrtc as webrtc_mod
+try:
+    from libervia.frontends.tools import webrtc as webrtc_mod
+except exceptions.MissingModule as e:
+    pytest.skip(
+        "Can't import webrtc due to missing modules: {e}",
+        allow_module_level=True
+    )
 
 
 @pytest.fixture