fix: Merge config child nodes on config.set()

The old behaviour will override child option nodes like options.client, causing properties to be lost if the new
option node is only partially specified. This partially causes karma-runner/grunt-karma#165 and
karma-runner/grunt-karma#166.

lib/config.js

@@ -5,6 +5,8 @@ var log = logger.create('config')
 var helper = require('./helper')
 var constant = require('./constants')
 
+var _ = require('lodash')
+
 var COFFEE_SCRIPT_AVAILABLE = false
 var LIVE_SCRIPT_AVAILABLE = false
 
@@ -226,8 +228,11 @@ var Config = function () {
   this.LOG_DEBUG = constant.LOG_DEBUG
 
   this.set = function (newConfig) {
-    Object.keys(newConfig).forEach(function (key) {
-      config[key] = newConfig[key]
+    _.merge(config, newConfig, function (obj, src) {
+      // Overwrite arrays to keep consistent with #283
+      if (_.isArray(src)) {
+        return src
+      }
     })
   }
 

test/unit/config.spec.js

@@ -39,6 +39,7 @@ describe('config', () => {
       '/home/config6.js': wrapCfg({reporters: 'junit'}),
       '/home/config7.js': wrapCfg({browsers: ['Chrome', 'Firefox']}),
       '/home/config8.js': (config) => config.set({ files: config.suite === 'e2e' ? ['tests/e2e.spec.js'] : ['tests/unit.spec.js'] }),
+      '/home/config9.js': wrapCfg({client: {useIframe: false}}),
       '/conf/invalid.js': () => { throw new SyntaxError('Unexpected token =') },
       '/conf/exclude.js': wrapCfg({exclude: ['one.js', 'sub/two.js']}),
       '/conf/absolute.js': wrapCfg({files: ['http://some.com', 'https://more.org/file.js']}),
@@ -138,13 +139,21 @@ describe('config', () => {
       expect(config.basePath).to.equal(resolveWinPath('/abs/base'))
     })
 
-    it('should override config with cli options, but not deep merge', () => {
+    it('should override config with cli options if the config property is an array', () => {
       // regression https://github.com/karma-runner/karma/issues/283
       var config = e.parseConfig('/home/config7.js', {browsers: ['Safari']})
 
       expect(config.browsers).to.deep.equal(['Safari'])
     })
 
+    it('should merge config with cli options if the config property is an object', () => {
+      // regression https://github.com/karma-runner/grunt-karma/issues/165
+      var config = e.parseConfig('/home/config9.js', {client: {captureConsole: false}})
+
+      expect(config.client.useIframe).to.equal(false)
+      expect(config.client.captureConsole).to.equal(false)
+    })
+
     it('should have access to cli options in the config file', () => {
       var config = e.parseConfig('/home/config8.js', {suite: 'e2e'})
       expect(patternsFrom(config.files)).to.deep.equal([resolveWinPath('/home/tests/e2e.spec.js')])