広場投稿追加画面の刷新 (#399) (#413)

Reviewed-on: #413
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

frontend/src/components/posts/import/PostImportThumbnailPreview.test.tsx

@@ -0,0 +1,59 @@
+import { fireEvent, render, screen } from '@testing-library/react'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import PostImportThumbnailPreview from '@/components/posts/import/PostImportThumbnailPreview'
+
+describe ('PostImportThumbnailPreview', () => {
+  beforeEach (() => {
+    vi.clearAllMocks ()
+    globalThis.URL.createObjectURL = vi.fn (() => 'blob:preview')
+    globalThis.URL.revokeObjectURL = vi.fn ()
+  })
+
+  it ('renders the remote URL directly without a backend proxy', () => {
+    render (
+	<PostImportThumbnailPreview
+	    url="https://example.com/thumbnail.jpg"
+	    className="h-10 w-10"/>)
+
+    expect (screen.getByRole ('img')).toHaveAttribute (
+	'src',
+	'https://example.com/thumbnail.jpg')
+    expect (screen.getByRole ('img')).toHaveAttribute (
+	'referrerpolicy',
+	'no-referrer')
+  })
+
+  it ('shows the empty frame after the remote image fails', () => {
+    const { container } = render (
+	<PostImportThumbnailPreview
+	    url="https://example.com/missing.jpg"
+	    className="h-10 w-10"/>)
+
+    fireEvent.error (screen.getByRole ('img'))
+
+    expect (screen.queryByRole ('img')).toBeNull ()
+    expect (container.querySelector ('div.rounded.border.bg-muted')).not.toBeNull ()
+    expect (container.textContent).toBe ('')
+  })
+
+  it ('uses and revokes an object URL only when the remote URL is blank', () => {
+    const file = new File (['image'], 'thumbnail.png', { type: 'image/png' })
+    const { rerender, unmount } = render (
+	<PostImportThumbnailPreview url="" file={file} className="h-10 w-10"/>)
+
+    expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:preview')
+
+    rerender (
+	<PostImportThumbnailPreview
+	    url="https://example.com/remote.jpg"
+	    file={file}
+	    className="h-10 w-10"/>)
+    expect (screen.getByRole ('img')).toHaveAttribute (
+	'src',
+	'https://example.com/remote.jpg')
+
+    unmount ()
+    expect (globalThis.URL.revokeObjectURL).toHaveBeenCalledWith ('blob:preview')
+  })
+})