Add require_module tests

tests/test_optional_dependencies.py

@@ -0,0 +1,15 @@
+import types
+import pytest
+
+from layerforge.utils.optional_dependencies import require_module
+
+
+def test_require_module_success():
+    mod = require_module("math", "Test")
+    assert isinstance(mod, types.ModuleType)
+
+
+def test_require_module_missing():
+    with pytest.raises(ImportError) as exc:
+        require_module("nonexistent_package_xyz", "MyFeature")
+    assert str(exc.value) == "MyFeature requires the 'nonexistent_package_xyz' package. Install it via 'pip install nonexistent_package_xyz'."