diff --git a/tests/test_scanner.py b/tests/test_scanner.py
index 7ab4ec2..61395c8 100644
--- a/tests/test_scanner.py
+++ b/tests/test_scanner.py
@@ -1,13 +1,13 @@
 """Scanner specific tests"""
 from __future__ import annotations
 
-from unittest import TestCase
+from unittest import TestCase, mock
 from unittest.mock import NonCallableMock, patch
 
 from faker import Faker
 from faker.providers import internet as internet_provider, python as python_provider
 
-from glocaltokens.scanner import NetworkDevice
+from glocaltokens.scanner import CastListener, NetworkDevice
 
 faker = Faker()  # type: ignore
 faker.add_provider(internet_provider)
@@ -41,13 +41,52 @@ def test_initialization(self) -> None:
         )
 
     @patch("glocaltokens.scanner.LOGGER.error")
-    def test_initialization__valid(self, mock: NonCallableMock) -> None:
-        """Valid initialization tests"""
-        NetworkDevice(
-            faker.word(),
-            faker.ipv4_private(),
-            faker.port_number(),
-            faker.word(),
-            faker.word(),
-        )
-        self.assertEqual(mock.call_count, 0)
+    def test_service_info__valid(self, m_error: NonCallableMock) -> None:
+        """Valid service_info tests"""
+        service = mock.Mock(name="Service")
+        service.parsed_addresses.return_value = None
+        service.server = faker.ipv4_private()
+        service.port = faker.port_number()
+
+        zc = mock.Mock(name="Zeroconf")
+        zc.get_service_info.return_value = service
+
+        listener = CastListener()
+        type_ = faker.word()
+        name = faker.word()
+        listener.add_service(zc, type_, name)
+        self.assertEqual(m_error.call_count, 0)
+
+    @patch("glocaltokens.scanner.LOGGER.error")
+    def test_service_info__invalid(self, m_error: NonCallableMock) -> None:
+        """Invalid service_info tests"""
+        service = mock.Mock(name="Service")
+        service.parsed_addresses.return_value = None
+
+        zc = mock.Mock(name="Zeroconf")
+        zc.get_service_info.return_value = service
+
+        listener = CastListener()
+        type_ = faker.word()
+        name = faker.word()
+
+        # With invalid IP
+        service.server = faker.word()
+        service.port = faker.port_number()
+        listener.add_service(zc, type_, name)
+        self.assertEqual(m_error.call_count, 1)
+
+        # With negative port
+        service.server = faker.ipv4_private()
+        service.port = faker.pyint(min_value=-9999, max_value=-1)
+        listener.add_service(zc, type_, name)
+        self.assertEqual(m_error.call_count, 2)
+
+        # With greater port
+        service.server = faker.ipv4_private()
+        service.port = faker.pyint(min_value=65535, max_value=999999)
+        listener.add_service(zc, type_, name)
+        self.assertEqual(m_error.call_count, 3)
+
+        # No devices should be added
+        self.assertEqual(listener.count, 0)