Add test code

Author: owjs3901

packages/webpack-plugin/src/__tests__/css-loader.test.ts

@@ -0,0 +1,16 @@
+import { getCss } from '@devup-ui/wasm'
+
+import devupUICssLoader from '../css-loader'
+
+vi.mock('@devup-ui/wasm')
+
+describe('devupUICssLoader', () => {
+  it('should invoke callback', () => {
+    vi.mocked(getCss).mockReturnValue('css')
+    const callback = vi.fn()
+    devupUICssLoader.bind({
+      callback,
+    } as any)(Buffer.from(''), '')
+    expect(callback).toBeCalledWith(null, 'css')
+  })
+})