diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29..26f49b4 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1,19 @@
+import logging
+from unittest import TestCase  # noqa: F401
+
+
+def patch_deprecation_warning():
+    original_logger = logging.getLogger("brother_ql.devicedependent").warning
+
+    def warn(message, *args, **kwargs):
+        if (
+            message
+            == "deprecation warning: brother_ql.devicedependent is deprecated and will be removed in a future release"  # noqa: E501
+        ):
+            return
+        original_logger(message, *args, **kwargs)
+
+    logging.getLogger("brother_ql.devicedependent").warn = warn
+
+
+patch_deprecation_warning()
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 86c24f1..af830c6 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1,8 +1,18 @@
-from unittest import TestCase
+from tests import TestCase  # Silence useless deprecation warning.
+
+from brother_ql_web import cli
 
 
 class LogLevelTypeTestCase(TestCase):
-    pass
+    def test_valid(self):
+        self.assertEqual(40, cli.log_level_type("ERROR"))
+        self.assertEqual(40, cli.log_level_type("error"))
+
+    def test_invalid(self):
+        with self.assertRaisesRegex(
+            AttributeError, "^module 'logging' has no attribute 'XYZ'$"
+        ):
+            cli.log_level_type("xyz")
 
 
 class GetParametersTestCase(TestCase):
diff --git a/tests/test_configuration.py b/tests/test_configuration.py
index e69de29..420ba88 100644
--- a/tests/test_configuration.py
+++ b/tests/test_configuration.py
@@ -0,0 +1,25 @@
+from unittest import TestCase
+
+
+class ConfigurationTestCase(TestCase):
+    pass
+
+
+class ServerConfigurationTestCase(TestCase):
+    pass
+
+
+class PrinterConfigurationTestCase(TestCase):
+    pass
+
+
+class FontTestCase(TestCase):
+    pass
+
+
+class LabelConfigurationTestCase(TestCase):
+    pass
+
+
+class WebsiteConfigurationTestCase(TestCase):
+    pass
diff --git a/tests/test_font_helpers.py b/tests/test_font_helpers.py
index e69de29..5b81cd6 100644
--- a/tests/test_font_helpers.py
+++ b/tests/test_font_helpers.py
@@ -0,0 +1,5 @@
+from unittest import TestCase
+
+
+class GetFontsTestCase(TestCase):
+    pass
diff --git a/tests/test_labels.py b/tests/test_labels.py
index e69de29..196b822 100644
--- a/tests/test_labels.py
+++ b/tests/test_labels.py
@@ -0,0 +1,29 @@
+from unittest import TestCase
+
+
+class LabelParametersTestCase(TestCase):
+    pass
+
+
+class DetermineImageDimensionsTestCase(TestCase):
+    pass
+
+
+class DetermineTextOffsetsTestCase(TestCase):
+    pass
+
+
+class CreateLabelImageTestCase(TestCase):
+    pass
+
+
+class ImageToPngBytesTestCase(TestCase):
+    pass
+
+
+class GenerateLabelTestCase(TestCase):
+    pass
+
+
+class PrintLabelTestCase(TestCase):
+    pass
diff --git a/tests/test_main.py b/tests/test_main.py
index e69de29..67c2e31 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -0,0 +1,5 @@
+from unittest import TestCase
+
+
+class MainTestCase(TestCase):
+    pass
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e69de29..20ce847 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -0,0 +1,13 @@
+from unittest import TestCase
+
+
+class CollectFontsTestCase(TestCase):
+    pass
+
+
+class GetLabelSizesTestCase(TestCase):
+    pass
+
+
+class GetBackendClassTestCase(TestCase):
+    pass
diff --git a/tests/test_web.py b/tests/test_web.py
index e69de29..c44c555 100644
--- a/tests/test_web.py
+++ b/tests/test_web.py
@@ -0,0 +1,33 @@
+from unittest import TestCase
+
+
+class GetConfigTestCase(TestCase):
+    pass
+
+
+class IndexTestCase(TestCase):
+    pass
+
+
+class ServeStaticTestCase(TestCase):
+    pass
+
+
+class LabeldesignerTestCase(TestCase):
+    pass
+
+
+class GetLabelParametersTestCase(TestCase):
+    pass
+
+
+class GetPreviewImageTestCase(TestCase):
+    pass
+
+
+class PrintTextTestCase(TestCase):
+    pass
+
+
+class MainTestCase(TestCase):
+    pass