Add a test for useInstanceVariable hook

src/web/hooks/__tests__/useInstanceVariable.jsx

@@ -0,0 +1,45 @@
+/* SPDX-FileCopyrightText: 2024 Greenbone AG
+ *
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+/* eslint-disable react/prop-types */
+
+import {describe, test, expect, testing} from '@gsa/testing';
+
+import {useCallback} from 'react';
+
+import {fireEvent, rendererWith, screen} from 'web/utils/testing';
+
+import useInstanceVariable from '../useInstanceVariable';
+
+const TestComponent = ({callback}) => {
+  const someVariable = useInstanceVariable({value: 1});
+  const changeValue = useCallback(() => {
+    someVariable.value = 2;
+    callback(someVariable.value);
+  }, [someVariable, callback]);
+  return (
+    <div>
+      <div data-testid="t1">{someVariable.value}</div>
+      <button data-testid="changeValue" onClick={changeValue} />
+    </div>
+  );
+};
+
+describe('useInstanceVariable tests', () => {
+  test('should render the value', () => {
+    const callback = testing.fn();
+    const {render} = rendererWith();
+
+    render(<TestComponent callback={callback} />);
+
+    const t1 = screen.getByTestId('t1');
+    expect(t1).toHaveTextContent('1');
+    const b1 = screen.getByTestId('changeValue');
+    fireEvent.click(b1);
+    expect(t1).toHaveTextContent('1');
+
+    expect(callback).toHaveBeenCalledWith(2);
+  });
+});