test: added test for MainAppSlot

src/plugin-slots/MainAppSlot/MainAppSlot.test.jsx

@@ -0,0 +1,29 @@
+import { PluginSlot } from '@openedx/frontend-plugin-framework';
+import { render } from '@testing-library/react';
+
+import MainAppSlot from './index';
+
+jest.mock('@openedx/frontend-plugin-framework', () => ({
+  PluginSlot: jest.fn(() => null),
+}));
+
+describe('MainAppSlot', () => {
+  it('renders without crashing', () => {
+    render(<MainAppSlot />);
+  });
+
+  it('renders a PluginSlot component', () => {
+    render(<MainAppSlot />);
+    expect(PluginSlot).toHaveBeenCalled();
+  });
+
+  it('passes the correct id prop to PluginSlot', () => {
+    render(<MainAppSlot />);
+    expect(PluginSlot).toHaveBeenCalledWith({ id: 'main_app_slot' }, {});
+  });
+
+  it('does not render any children', () => {
+    const { container } = render(<MainAppSlot />);
+    expect(container.firstChild).toBeNull();
+  });
+});