test(e2e): force IPv4 for hosted test origin

Accept safe dual-stack loopback resolution while pinning Chromium and Node traffic to 127.0.0.1 so CI reaches IPv4-only services reliably.

Author: Bill Leoutsakos

apps/sim/e2e/README.md

@@ -16,7 +16,9 @@ per-run pgvector database.
    echo "127.0.0.1 e2e.sim.ai" | sudo tee -a /etc/hosts
    ```
 
-   The runner refuses to start unless every resolved address is loopback.
+   The runner refuses to start unless every resolved address is loopback and an
+   IPv4 `127.0.0.1` result is present. Chromium and Node are configured to prefer
+   that IPv4 mapping, so CI environments that also synthesize `::1` remain safe.
 
 2. Start a local pgvector/Postgres admin instance:
 

apps/sim/e2e/foundation/safety.spec.ts

@@ -84,7 +84,7 @@ test.describe('foundation safety guards', () => {
     expect(isLoopbackAddress('::1')).toBe(true)
     expect(isLoopbackAddress('8.8.8.8')).toBe(false)
     expect(areValidE2eHostAddresses(['127.0.0.1'])).toBe(true)
-    expect(areValidE2eHostAddresses(['127.0.0.1', '::1'])).toBe(false)
+    expect(areValidE2eHostAddresses(['127.0.0.1', '::1'])).toBe(true)
     expect(areValidE2eHostAddresses(['::1'])).toBe(false)
     expect(areValidE2eHostAddresses(['127.0.0.2'])).toBe(false)
   })

apps/sim/e2e/support/deployment-profile.ts

@@ -63,7 +63,7 @@ export function createHostedBillingProfile({
 }: HostedBillingProfileOptions): HostedBillingProfile {
   const values: Record<string, string> = {
     NODE_ENV: 'production',
-    NODE_OPTIONS: '--no-warnings --max-old-space-size=8192',
+    NODE_OPTIONS: '--no-warnings --max-old-space-size=8192 --dns-result-order=ipv4first',
     NEXT_TELEMETRY_DISABLED: '1',
     HOME: homeDirectory,
     XDG_CONFIG_HOME: `${homeDirectory}/xdg`,

apps/sim/e2e/support/hosts.ts

@@ -12,7 +12,9 @@ export function isLoopbackAddress(address: string): boolean {
 }
 
 export function areValidE2eHostAddresses(addresses: string[]): boolean {
-  return addresses.length > 0 && addresses.every((address) => address === '127.0.0.1')
+  return (
+    addresses.length > 0 && addresses.every(isLoopbackAddress) && addresses.includes('127.0.0.1')
+  )
 }
 
 export async function assertE2eHostResolvesToLoopback(hostname = E2E_HOST): Promise<string[]> {
@@ -33,7 +35,7 @@ export async function assertE2eHostResolvesToLoopback(hostname = E2E_HOST): Prom
 function getHostMappingError(hostname: string, addresses: string[]): string {
   const observed = addresses.length > 0 ? addresses.join(', ') : 'no addresses'
   return [
-    `${hostname} must resolve exclusively to IPv4 127.0.0.1; observed ${observed}.`,
+    `${hostname} must resolve only to loopback and include IPv4 127.0.0.1; observed ${observed}.`,
     `Add it once with: echo "127.0.0.1 ${hostname}" | sudo tee -a /etc/hosts`,
   ].join(' ')
 }

apps/sim/playwright.config.ts

@@ -29,6 +29,9 @@ export default defineConfig({
   use: {
     ...devices['Desktop Chrome'],
     baseURL,
+    launchOptions: {
+      args: ['--host-resolver-rules=MAP e2e.sim.ai 127.0.0.1'],
+    },
     actionTimeout: 15_000,
     navigationTimeout: 30_000,
     trace: 'retain-on-failure',