test(dialog): lazy mount behavior (#1847)

src/components/ui/Dialog/tests/Dialog.lazyMount.test.tsx

@@ -0,0 +1,52 @@
+import React from 'react';
+import { render, screen } from '@testing-library/react';
+import Dialog from '../Dialog';
+import Theme from '~/components/ui/Theme/Theme';
+
+const mockMatchMedia = () => {
+    if ('matchMedia' in window && typeof window.matchMedia === 'function') return;
+    Object.defineProperty(window, 'matchMedia', {
+        writable: true,
+        value: jest.fn().mockImplementation(() => ({
+            matches: false,
+            addEventListener: jest.fn(),
+            removeEventListener: jest.fn()
+        }))
+    });
+};
+
+describe('Dialog lazy mount behavior', () => {
+    beforeEach(() => mockMatchMedia());
+
+    test('does not mount content while closed by default', () => {
+        render(
+            <Theme>
+                <Dialog.Root open={false}>
+                    <Dialog.Trigger>Open</Dialog.Trigger>
+                    <Dialog.Portal>
+                        <Dialog.Content>Hidden dialog</Dialog.Content>
+                    </Dialog.Portal>
+                </Dialog.Root>
+            </Theme>
+        );
+
+        expect(screen.getByText('Open')).toBeInTheDocument();
+        expect(screen.queryByText('Hidden dialog')).not.toBeInTheDocument();
+    });
+
+    test('forceMount keeps content mounted while closed', () => {
+        render(
+            <Theme>
+                <Dialog.Root open={false}>
+                    <Dialog.Trigger>Open</Dialog.Trigger>
+                    <Dialog.Portal>
+                        <Dialog.Content forceMount>Mounted dialog</Dialog.Content>
+                    </Dialog.Portal>
+                </Dialog.Root>
+            </Theme>
+        );
+
+        expect(screen.getByText('Mounted dialog')).toBeInTheDocument();
+        expect(screen.getByText('Mounted dialog')).toHaveAttribute('data-state', 'closed');
+    });
+});