add callback tests

Signed-off-by: Thijs Baaijen <[email protected]>

Author: Thijss

tests/unit/visualizer/test_callbacks.py

@@ -0,0 +1,27 @@
+# SPDX-FileCopyrightText: 2025 Contributors to the Power Grid Model project <[email protected]>
+#
+# SPDX-License-Identifier: MPL-2.0
+
+from power_grid_model_ds._core.visualizer.callbacks.element_scaling import scale_elements
+from power_grid_model_ds._core.visualizer.callbacks.search_form import search_element
+from power_grid_model_ds._core.visualizer.layout.cytoscape_styling import DEFAULT_STYLESHEET
+
+
+def test_scale_elements():
+    assert scale_elements(1, 1)
+
+
+def test_search_element_no_input():
+    assert search_element(group="", column="", operator="", value="") == DEFAULT_STYLESHEET
+
+
+def test_search_element_with_input():
+    group = "node"
+    column = "id"
+    operator = "="
+    value = "1"
+
+    expected_selector = f'[{column} {operator} "{value}"]'
+
+    result = search_element(group, column, operator, value)
+    assert result[-1]["selector"] == expected_selector