test: fix test-debug-port-from-cmdline

test/simple/test-debug-port-from-cmdline.js

@@ -24,11 +24,11 @@ var assert = require('assert');
 var spawn = require('child_process').spawn;
 
 var debugPort = common.PORT;
-var args = ['--debug-port=' + debugPort];
+var args = ['--interactive', '--debug-port=' + debugPort];
 var childOptions = { stdio: ['pipe', 'pipe', 'pipe', 'ipc'] };
 var child = spawn(process.execPath, args, childOptions);
 
-child.stdin.end("process.send({ msg: 'childready' });");
+child.stdin.write("process.send({ msg: 'childready' });\n");
 
 child.stderr.on('data', function(data) {
   var lines = data.toString().replace(/\r/g, '').trim().split('\n');
@@ -43,6 +43,7 @@ child.on('message', function onChildMsg(message) {
 
 process.on('exit', function() {
   child.kill();
+  assertOutputLines();
 });
 
 var outputLines = [];
@@ -51,7 +52,6 @@ function processStderrLine(line) {
   outputLines.push(line);
 
   if (/Debugger listening/.test(line)) {
-    assertOutputLines();
     process.exit();
   }
 }