task-34: HTTP 4xx/5xx 分类

8 个测试固化 HTTP 错误语义：4xx/5xx 记 onError 并进入退避、
不触发 onTerminal（5xx 不可解析明细时不误判 FAILED）、不清空已有
状态、恢复后继续轮询且部分 items 照常处理、未知状态不受影响。

行为由 http 层抛错与既有 catch 路径实现，本次为验证型测试。

frontend-vue/tests/polling-http-error-class.test.ts

@@ -0,0 +1,141 @@
+import { test } from 'node:test'
+import assert from 'node:assert/strict'
+import { useTaskProgressLoop } from '../src/shared/composables/useTaskProgressLoop.ts'
+
+function setupWindow() {
+  const storage = new Map<string, string>()
+  ;(globalThis as Record<string, unknown>).window = {
+    localStorage: {
+      getItem: (k: string) => storage.get(k) ?? null,
+      setItem: (k: string, v: string) => { storage.set(k, v) },
+      removeItem: (k: string) => { storage.delete(k) },
+    },
+    setTimeout: (fn: () => void, ms: number) => globalThis.setTimeout(fn, ms),
+    clearTimeout: (id: unknown) => globalThis.clearTimeout(id as number),
+    setInterval: (fn: () => void, ms: number) => globalThis.setInterval(fn, ms),
+    clearInterval: (id: unknown) => globalThis.clearInterval(id as number),
+  }
+}
+
+let scopeCounter = 0
+
+function httpError(status: number, data?: unknown): Error {
+  const err = new Error(`Request failed with status code ${status}`) as Error & {
+    isAxiosError?: boolean
+    response?: { status: number; data?: unknown }
+  }
+  err.isAxiosError = true
+  err.response = { status, data }
+  return err
+}
+
+interface Harness {
+  loop: ReturnType<typeof useTaskProgressLoop<{ taskId?: number; status?: string }>>
+  terminalCalls: Array<{ taskId: number; status: string }>
+  errorCalls: unknown[]
+}
+
+async function makeLoop(impl: () => Promise<{ items: unknown[] }>): Promise<Harness> {
+  const terminalCalls: Array<{ taskId: number; status: string }> = []
+  const errorCalls: unknown[] = []
+  const loop = useTaskProgressLoop<{ taskId?: number; status?: string }>({
+    scope: `http-err-${scopeCounter++}`,
+    fetchProgress: async () => impl(),
+    extractTaskId: (d) => d?.taskId,
+    extractStatus: (d) => d?.status,
+    getIntervalMs: () => 60000,
+    onTerminal: (taskId, _d, status) => { terminalCalls.push({ taskId, status }) },
+    onError: (e) => { errorCalls.push(e) },
+  })
+  loop.reset([1])
+  await new Promise<void>((r) => globalThis.setTimeout(r, 0))
+  return { loop, terminalCalls, errorCalls }
+}
+
+test('test_4xx_on_error', async () => {
+  setupWindow()
+  const h = await makeLoop(async () => { throw httpError(404) })
+  await h.loop.refreshOnce()
+  assert.equal(h.errorCalls.length, 2, '4xx 记 onError')
+  h.loop.dispose()
+})
+
+test('test_5xx_on_error', async () => {
+  setupWindow()
+  const h = await makeLoop(async () => { throw httpError(500) })
+  await h.loop.refreshOnce()
+  assert.equal(h.errorCalls.length, 2, '5xx 记 onError')
+  h.loop.dispose()
+})
+
+test('test_5xx_no_terminal_failed', async () => {
+  setupWindow()
+  const h = await makeLoop(async () => { throw httpError(503, { message: 'upstream down' }) })
+  await h.loop.refreshOnce()
+  assert.equal(h.terminalCalls.length, 0, '5xx 且无法解析明细时不误判 FAILED')
+  h.loop.dispose()
+})
+
+test('test_5xx_backoff', async () => {
+  setupWindow()
+  const h = await makeLoop(async () => { throw httpError(500) })
+  const before = h.errorCalls.length
+  await new Promise<void>((r) => globalThis.setTimeout(r, 50))
+  assert.equal(h.errorCalls.length, before, '5xx 后不立即自动重试（退避）')
+  h.loop.dispose()
+})
+
+test('test_5xx_unknown_status_untouched', async () => {
+  setupWindow()
+  let fail = true
+  const h = await makeLoop(async () => {
+    if (fail) throw httpError(500)
+    return { items: [{ taskId: 1, status: 'WEIRD_STATE' }] }
+  })
+  fail = false
+  await h.loop.refreshOnce()
+  assert.equal(h.loop.taskStatuses.value[1], 'WEIRD_STATE', '恢复后未知状态照常落地')
+  assert.equal(h.terminalCalls.length, 0, '未知状态不触发终态')
+  h.loop.dispose()
+})
+
+test('test_4xx_recovery', async () => {
+  setupWindow()
+  let fail = true
+  const h = await makeLoop(async () => {
+    if (fail) throw httpError(400)
+    return { items: [{ taskId: 1, status: 'RUNNING' }] }
+  })
+  await h.loop.refreshOnce()
+  fail = false
+  await h.loop.refreshOnce()
+  assert.equal(h.loop.taskStatuses.value[1], 'RUNNING', '4xx 后恢复继续轮询')
+  h.loop.dispose()
+})
+
+test('test_status_500_partial_items', async () => {
+  setupWindow()
+  let fail = true
+  const h = await makeLoop(async () => {
+    if (fail) throw httpError(500)
+    return { items: [{ taskId: 1, status: 'SUCCESS' }, { taskId: 2, status: 'RUNNING' }] }
+  })
+  fail = false
+  await h.loop.refreshOnce()
+  assert.equal(h.terminalCalls.length, 1, '5xx 恢复后部分 items 仍处理')
+  assert.equal(h.terminalCalls[0].taskId, 1)
+  assert.equal(h.loop.taskStatuses.value[2], 'RUNNING')
+  h.loop.dispose()
+})
+
+test('test_5xx_no_status_wipe', async () => {
+  setupWindow()
+  const h = await makeLoop(async () => { throw httpError(500) })
+  // 先正常落地一个状态，再出现 5xx
+  const loop2 = h.loop
+  const original = loop2.taskStatuses
+  original.value = { 1: 'RUNNING' }
+  await loop2.refreshOnce()
+  assert.equal(loop2.taskStatuses.value[1], 'RUNNING', '5xx 不清空已有状态')
+  loop2.dispose()
+})