Ensure required-server-files test doesn't get stuck on failure (verce…

…l#67576)

This test suite is failing with Turbopack build and when it fails the
suite gets stuck because it will wait on each test case even though the
command has failed.

Introduced it as a new flag on the util as this is a legacy test helper
that we no longer use in new tests and I don't want to break existing
tests that might be checking non-zero exit codes.

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test/lib/next-test-utils.ts

@@ -46,6 +46,8 @@ export function initNextServerScript(
     nodeArgs?: string[]
     onStdout?: (data: any) => void
     onStderr?: (data: any) => void
+    // If true, the promise will reject if the process exits with a non-zero code
+    shouldRejectOnError?: boolean
   }
 ): Promise<ChildProcess> {
   return new Promise((resolve, reject) => {
@@ -83,6 +85,14 @@ export function initNextServerScript(
       }
     }
 
+    if (opts?.shouldRejectOnError) {
+      instance.on('exit', (code) => {
+        if (code !== 0) {
+          reject(new Error('exited with code: ' + code))
+        }
+      })
+    }
+
     instance.stdout.on('data', handleStdout)
     instance.stderr.on('data', handleStderr)
 

test/production/standalone-mode/required-server-files/required-server-files.test.ts

@@ -142,6 +142,7 @@ describe('required server files', () => {
           errors.push(msg)
           stderr += msg
         },
+        shouldRejectOnError: true,
       }
     )
   })