Add tests for deprecation helpers
diff --git a/tests/helpers/test_deprecation.py b/tests/helpers/test_deprecation.py
new file mode 100644
index 000000000000..8064c2ea5d67
--- /dev/null
+++ b/tests/helpers/test_deprecation.py
@@ -0,0 +1,85 @@
+"""Test deprecation helpers."""
+from homeassistant.helpers.deprecation import (
+    deprecated_substitute, get_deprecated)
+
+from unittest.mock import patch, MagicMock
+
+
+class MockBaseClass():
+    """Mock base class for deprecated testing."""
+
+    @property
+    @deprecated_substitute('old_property')
+    def new_property(self):
+        """Test property to fetch."""
+        raise NotImplementedError()
+
+
+class MockDeprecatedClass(MockBaseClass):
+    """Mock deprecated class object."""
+
+    @property
+    def old_property(self):
+        """Test property to fetch."""
+        return True
+
+
+class MockUpdatedClass(MockBaseClass):
+    """Mock updated class object."""
+
+    @property
+    def new_property(self):
+        """Test property to fetch."""
+        return True
+
+
+@patch('logging.getLogger')
+def test_deprecated_substitute_old_class(mock_get_logger):
+    """Test deprecated class object."""
+    mock_logger = MagicMock()
+    mock_get_logger.return_value = mock_logger
+
+    mock_object = MockDeprecatedClass()
+    assert mock_object.new_property is True
+    assert mock_object.new_property is True
+    assert mock_logger.warning.called
+    assert len(mock_logger.warning.mock_calls) == 1
+
+
+@patch('logging.getLogger')
+def test_deprecated_substitute_new_class(mock_get_logger):
+    """Test deprecated class object."""
+    mock_logger = MagicMock()
+    mock_get_logger.return_value = mock_logger
+
+    mock_object = MockUpdatedClass()
+    assert mock_object.new_property is True
+    assert mock_object.new_property is True
+    assert not mock_logger.warning.called
+
+
+@patch('logging.getLogger')
+def test_config_get_deprecated_old(mock_get_logger):
+    """Test deprecated class object."""
+    mock_logger = MagicMock()
+    mock_get_logger.return_value = mock_logger
+
+    config = {
+        'old_name': True,
+    }
+    assert get_deprecated(config, 'new_name', 'old_name') is True
+    assert mock_logger.warning.called
+    assert len(mock_logger.warning.mock_calls) == 1
+
+
+@patch('logging.getLogger')
+def test_config_get_deprecated_new(mock_get_logger):
+    """Test deprecated class object."""
+    mock_logger = MagicMock()
+    mock_get_logger.return_value = mock_logger
+
+    config = {
+        'new_name': True,
+    }
+    assert get_deprecated(config, 'new_name', 'old_name') is True
+    assert not mock_logger.warning.called

## Description:
Add tests for deprecation helpers