pipe streams and ignore stderr, close #557 (#560)

cli/lib/exec/spawn.js

@@ -1,6 +1,7 @@
 const _ = require('lodash')
 const cp = require('child_process')
 const Promise = require('bluebird')
+const devNull = require('dev-null')
 const debug = require('debug')('cypress:cli')
 
 const info = require('../tasks/info')
@@ -13,7 +14,7 @@ module.exports = {
 
     _.defaults(options, {
       detached: false,
-      stdio: [process.stdin, process.stdout, 'ignore'],
+      stdio: ['inherit', 'pipe', 'pipe'],
     })
 
     const spawn = () => {
@@ -26,6 +27,9 @@ module.exports = {
         child.on('close', resolve)
         child.on('error', reject)
 
+        child.stdout.pipe(process.stdout)
+        child.stderr.pipe(devNull())
+
         if (options.detached) {
           child.unref()
         }

cli/package.json

@@ -30,6 +30,7 @@
     "commander": "2.9.0",
     "common-tags": "1.4.0",
     "debug": "2.6.8",
+    "dev-null": "0.1.1",
     "extract-zip": "1.6.5",
     "fs-extra": "4.0.1",
     "getos": "2.8.4",

cli/test/lib/exec/spawn_spec.js

@@ -12,6 +12,12 @@ describe('exec spawn', function () {
     this.spawnedProcess = this.sandbox.stub({
       on: () => {},
       unref: () => {},
+      stdout: {
+        pipe: () => {},
+      },
+      stderr: {
+        pipe: () => {},
+      },
     })
     this.sandbox.stub(cp, 'spawn').returns(this.spawnedProcess)
     this.sandbox.stub(xvfb, 'start').resolves()