Add unit tests for LoginButton component with comprehensive coverage

frontend/vue-app/src/common/imageCache.ts

@@ -9,6 +9,7 @@ export async function getCachedImageUrl(
   if (!imageId) throw new Error('imageId required')
 
   // reuse existing object URL if created in this session
+  console.log('Checking existing object URL for imageId:', imageId)
   const existing = objectUrlMap.get(imageId)
   if (existing) return existing
 
@@ -23,6 +24,7 @@ export async function getCachedImageUrl(
       const fetched = await fetch(requestUrl)
       if (!fetched.ok) throw new Error(`HTTP ${fetched.status}`)
       // store a clone in Cache Storage (non-blocking)
+      console.log('Caching image:', requestUrl)
       cache.put(requestUrl, fetched.clone()).catch((e) => {
         console.warn('Cache put failed:', e)
       })
@@ -40,6 +42,31 @@ export async function getCachedImageUrl(
   return objectUrl
 }
 
+export async function getCachedImageBlob(
+  imageId: string,
+  cacheName = DEFAULT_IMAGE_CACHE,
+): Promise<Blob> {
+  if (!imageId) throw new Error('imageId required')
+  const requestUrl = `/api/image/request/${imageId}`
+
+  let response: Response | undefined
+  if ('caches' in window) {
+    const cache = await caches.open(cacheName)
+    response = await cache.match(requestUrl)
+    if (!response) {
+      const fetched = await fetch(requestUrl)
+      if (!fetched.ok) throw new Error(`HTTP ${fetched.status}`)
+      cache.put(requestUrl, fetched.clone()).catch(() => {})
+      response = fetched
+    }
+  } else {
+    const fetched = await fetch(requestUrl)
+    if (!fetched.ok) throw new Error(`HTTP ${fetched.status}`)
+    response = fetched
+  }
+  return await response.blob()
+}
+
 export function revokeImageUrl(imageId: string) {
   const url = objectUrlMap.get(imageId)
   if (url) {