diff --git a/kiauh/extensions/tests/__init__.py b/kiauh/extensions/tests/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/kiauh/extensions/tests/test_base_extension.py b/kiauh/extensions/tests/test_base_extension.py
new file mode 100644
index 00000000..d1ef72e9
--- /dev/null
+++ b/kiauh/extensions/tests/test_base_extension.py
@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import pytest
+from extensions.base_extension import BaseExtension
+
+
+class ConcreteExtension(BaseExtension):
+    def install_extension(self, **kwargs) -> None:
+        pass
+
+    def remove_extension(self, **kwargs) -> None:
+        pass
+
+
+class TestBaseExtension:
+    def test_concrete_subclass_can_be_instantiated(self) -> None:
+        ext = ConcreteExtension({"name": "test"})
+        assert ext.metadata["name"] == "test"
+
+    def test_update_extension_not_implemented(self) -> None:
+        ext = ConcreteExtension({"name": "test"})
+        with pytest.raises(NotImplementedError):
+            ext.update_extension()
+
+    def test_abstract_methods_enforced(self) -> None:
+        class PartialExtension(BaseExtension):
+            def install_extension(self, **kwargs) -> None:
+                pass
+
+        with pytest.raises(TypeError):
+            PartialExtension({"name": "test"})