chore: import upstream snapshot with attribution

apps/sim/lib/core/config/appconfig.test.ts

@@ -0,0 +1,136 @@
+/**
+ * @vitest-environment node
+ */
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockSend } = vi.hoisted(() => ({
+  mockSend: vi.fn(),
+}))
+
+vi.mock('@aws-sdk/client-appconfigdata', () => ({
+  AppConfigDataClient: class {
+    send = mockSend
+  },
+  StartConfigurationSessionCommand: class {
+    __type = 'start'
+    constructor(public input: unknown) {}
+  },
+  GetLatestConfigurationCommand: class {
+    __type = 'get'
+    constructor(public input: unknown) {}
+  },
+}))
+
+import { fetchAppConfigProfile } from '@/lib/core/config/appconfig'
+
+const encode = (value: unknown) => new TextEncoder().encode(JSON.stringify(value))
+
+let counter = 0
+/** Unique identifiers per test so the module-level cache never bleeds across tests. */
+function uniqueIds() {
+  counter += 1
+  return { application: `app-${counter}`, environment: `env-${counter}`, profile: 'access-control' }
+}
+
+describe('fetchAppConfigProfile', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('starts a session then returns the parsed configuration', async () => {
+    mockSend.mockImplementation((command: { __type: string }) => {
+      if (command.__type === 'start') return Promise.resolve({ InitialConfigurationToken: 'tok-1' })
+      return Promise.resolve({
+        Configuration: encode({ blockedSignupDomains: ['spam.example'] }),
+        NextPollConfigurationToken: 'tok-2',
+      })
+    })
+
+    const result = await fetchAppConfigProfile(
+      uniqueIds(),
+      (json) => json as Record<string, unknown>
+    )
+    expect(result).toEqual({ blockedSignupDomains: ['spam.example'] })
+
+    const sentTypes = mockSend.mock.calls.map(([c]) => c.__type)
+    expect(sentTypes).toEqual(['start', 'get'])
+  })
+
+  it('returns null when the cold fetch fails (never throws)', async () => {
+    mockSend.mockRejectedValue(new Error('appconfig down'))
+    const result = await fetchAppConfigProfile(uniqueIds(), (json) => json)
+    expect(result).toBeNull()
+  })
+
+  it('applies the parse function to the decoded JSON', async () => {
+    mockSend.mockImplementation((command: { __type: string }) => {
+      if (command.__type === 'start') return Promise.resolve({ InitialConfigurationToken: 'tok-1' })
+      return Promise.resolve({
+        Configuration: encode({ count: 2 }),
+        NextPollConfigurationToken: 'tok-2',
+      })
+    })
+
+    const result = await fetchAppConfigProfile(
+      uniqueIds(),
+      (json) => (json as { count: number }).count * 10
+    )
+    expect(result).toBe(20)
+  })
+
+  it('warms the cache on an empty payload and does not re-poll (unseeded profile)', async () => {
+    mockSend.mockImplementation((command: { __type: string }) => {
+      if (command.__type === 'start') return Promise.resolve({ InitialConfigurationToken: 'tok-1' })
+      return Promise.resolve({
+        Configuration: new Uint8Array(),
+        NextPollConfigurationToken: 'tok-2',
+        NextPollIntervalInSeconds: 60,
+      })
+    })
+
+    const ids = uniqueIds()
+    expect(await fetchAppConfigProfile(ids, (json) => json)).toBeNull()
+    const callsAfterFirst = mockSend.mock.calls.length
+
+    expect(await fetchAppConfigProfile(ids, (json) => json)).toBeNull()
+    expect(mockSend.mock.calls.length).toBe(callsAfterFirst)
+  })
+
+  it('keeps the session on a parse error (no re-StartConfigurationSession, no throw)', async () => {
+    mockSend.mockImplementation((command: { __type: string }) => {
+      if (command.__type === 'start') return Promise.resolve({ InitialConfigurationToken: 'tok-1' })
+      return Promise.resolve({
+        Configuration: new TextEncoder().encode('not json{'),
+        NextPollConfigurationToken: 'tok-2',
+        NextPollIntervalInSeconds: 60,
+      })
+    })
+
+    const ids = uniqueIds()
+    expect(await fetchAppConfigProfile(ids, (json) => json)).toBeNull()
+
+    // Network round trip succeeded, so exactly one session was started despite the
+    // parse failure — the rotated token was preserved, not discarded.
+    expect(mockSend.mock.calls.filter(([c]) => c.__type === 'start')).toHaveLength(1)
+  })
+
+  it('dedupes concurrent cold fetches into a single poll', async () => {
+    mockSend.mockImplementation((command: { __type: string }) => {
+      if (command.__type === 'start') return Promise.resolve({ InitialConfigurationToken: 'tok-1' })
+      return Promise.resolve({
+        Configuration: encode({ x: 1 }),
+        NextPollConfigurationToken: 'tok-2',
+      })
+    })
+
+    const ids = uniqueIds()
+    const [a, b] = await Promise.all([
+      fetchAppConfigProfile(ids, (json) => json),
+      fetchAppConfigProfile(ids, (json) => json),
+    ])
+
+    expect(a).toEqual({ x: 1 })
+    expect(b).toEqual({ x: 1 })
+    expect(mockSend.mock.calls.map(([c]) => c.__type)).toEqual(['start', 'get'])
+  })
+})