补齐图片选择器关闭与空状态测试

新增遮罩点击关闭和空素材列表场景覆盖。

apps/ai-game-creator-shell/tests/imageAssetSelector.test.tsx

@@ -34,11 +34,12 @@ function renderSelector(
   value: string | null = null,
   onChange = vi.fn(),
   previewUrls: Record<string, string> = {},
+  selectorSprites: typeof sprites = sprites,
 ) {
   return render(
     <ImageAssetSelector
       value={value}
-      sprites={sprites}
+      sprites={selectorSprites}
       previewUrls={previewUrls}
       readOnly={false}
       onChange={onChange}
@@ -135,4 +136,26 @@ describe('ImageAssetSelector', () => {
     await user.keyboard('{Enter}');
     expect(onChange).toHaveBeenCalledWith('hero');
   });
+
+  it('closes when the modal backdrop is clicked', async () => {
+    const user = userEvent.setup();
+    renderSelector();
+    await user.click(screen.getByRole('button', { name: '选择素材' }));
+    const dialog = screen.getByRole('dialog', { name: '选择图片素材' });
+    const overlay = dialog.parentElement;
+    expect(overlay).toBeTruthy();
+    await user.click(overlay!);
+    expect(screen.queryByRole('dialog', { name: '选择图片素材' })).toBeNull();
+  });
+
+  it('shows an empty state when no sprites are available', async () => {
+    const user = userEvent.setup();
+    renderSelector(null, vi.fn(), {}, {});
+    await user.click(screen.getByRole('button', { name: '选择素材' }));
+    const dialog = screen.getByRole('dialog', { name: '选择图片素材' });
+    expect(within(dialog).getByText('暂无可用素材')).toBeTruthy();
+    expect(
+      within(dialog).getByRole('button', { name: /清除选择/ }),
+    ).toBeTruthy();
+  });
 });