[cli] Add test for CLI extensions passing through exit code (#11600)

/cc @codybrouwers

.changeset/gorgeous-cycles-sell.md

@@ -0,0 +1,2 @@
+---
+---

packages/cli/test/fixtures/e2e/cli-extension-exit-code/package.json

@@ -0,0 +1,6 @@
+{
+  "private": true,
+  "dependencies": {
+    "cli-extension-fail": "file:../cli-extension-fail"
+  }
+}

packages/cli/test/fixtures/e2e/cli-extension-fail/bin.js

@@ -0,0 +1,2 @@
+#!/usr/bin/env node
+process.exit(6);

packages/cli/test/fixtures/e2e/cli-extension-fail/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "cli-extension-fail",
+  "bin": {
+    "vercel-fail": "bin.js"
+  }
+}

packages/cli/test/integration-3.test.ts

@@ -1327,6 +1327,19 @@ test('should invoke CLI extension', async () => {
   expect(output.stdout, formatted).toContain(`Username: ${contextName}`);
 });
 
+test('should pass through exit code for CLI extension', async () => {
+  const fixture = path.join(__dirname, 'fixtures/e2e/cli-extension-exit-code');
+
+  // Ensure the `.bin` is populated in the fixture
+  await runNpmInstall(fixture);
+
+  const output = await execCli(binaryPath, ['fail'], {
+    cwd: fixture,
+    reject: false,
+  });
+  expect(output.exitCode).toEqual(6);
+});
+
 // NOTE: Order matters here. This must be the last test in the file.
 test('default command should prompt login with empty auth.json', async () => {
   await clearAuthConfig();