diff --git a/tests/conftest.py b/tests/conftest.py
index a55d60684..35538180f 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -4,15 +4,26 @@ from unittest.mock import MagicMock, PropertyMock, patch
 import pytest
 
 from supervisor.bootstrap import initialize_coresys
+from supervisor.docker import DockerAPI
 
 # pylint: disable=redefined-outer-name, protected-access
 
 
 @pytest.fixture
 def docker():
-    """Mock Docker API."""
-    with patch("supervisor.coresys.DockerAPI") as mock:
-        yield mock
+    """Mock DockerAPI."""
+    images = [MagicMock(tags=["homeassistant/amd64-hassio-supervisor:latest"])]
+
+    with patch("docker.DockerClient", return_value=MagicMock()), patch(
+        "supervisor.docker.DockerAPI.images", return_value=MagicMock()
+    ), patch("supervisor.docker.DockerAPI.containers", return_value=MagicMock()), patch(
+        "supervisor.docker.DockerAPI.api", return_value=MagicMock()
+    ), patch(
+        "supervisor.docker.DockerAPI.images.list", return_value=images
+    ):
+        docker_obj = DockerAPI()
+
+        yield docker_obj
 
 
 @pytest.fixture
diff --git a/tests/docker/test_denylist.py b/tests/docker/test_denylist.py
new file mode 100644
index 000000000..be40ddce9
--- /dev/null
+++ b/tests/docker/test_denylist.py
@@ -0,0 +1,15 @@
+"""Test tags in denylist."""
+
+from unittest.mock import MagicMock, patch
+
+
+def test_has_images_in_denylist(docker):
+    """Test tags in denylist exsist."""
+    images = [MagicMock(tags=["containrrr/watchtower:latest"])]
+    with patch("supervisor.docker.DockerAPI.images.list", return_value=images):
+        assert docker.check_denylist_images()
+
+
+def test_no_images_in_denylist(docker):
+    """Test tags in denylist does not exsist."""
+    assert not docker.check_denylist_images()