feat(web-server): allow overriding of default http module

allow setting an external module for use by KarmaServer

Closes #2424

docs/config/01-configuration-file.md

@@ -537,6 +537,17 @@ Determines the use of the Node `http` or `https` class.
 Note: Using `'https:'` requires you to specify `httpsServerOptions`.
 
 
+## httpModule
+**Type:** String
+
+**Default:** `undefined`
+
+**Description:** Module used for Karma webserver.
+
+Uses the provided module instead of node's built in `http` or `https` module. The module loaded here must exactly match the interface of node's http module. This can be useful for loading in a module like `node-http2` to allow for http2 support. 
+
+Note: if you're using this to enable `http2` you must also set the `protocol` to `https:` and specify certificates as http2 can only run of https.
+
 ## proxies
 **Type:** Object
 

lib/web-server.js

@@ -92,6 +92,11 @@ var createWebServer = function (injector, emitter, fileList) {
     serverClass = https
     serverArguments.unshift(config.httpsServerOptions || {})
   }
+
+  if (config.httpModule) {
+    serverClass = config.httpModule
+  }
+
   var server = serverClass.createServer.apply(null, serverArguments)
 
   server.on('upgrade', function (req, socket, head) {

package.json

@@ -353,6 +353,7 @@
     "grunt-eslint": "^18.0.0",
     "grunt-mocha-test": "^0.12.7",
     "grunt-npm": "0.0.2",
+    "http2": "^3.3.6",
     "jasmine-core": "^2.3.4",
     "json3": "^3.3.2",
     "karma-browserify": "^5.0.1",

test/unit/web-server.spec.js

@@ -240,4 +240,35 @@ describe('web-server', () => {
         .expect(200, 'CLIENT HTML')
     })
   })
+
+  describe('http2', () => {
+    var http2 = require('http2')
+
+    beforeEach(() => {
+      var credentials = {
+        key: fs.readFileSync(path.join(__dirname, '/certificates/server.key')),
+        cert: fs.readFileSync(path.join(__dirname, '/certificates/server.crt'))
+      }
+
+      customFileHandlers = []
+      emitter = new EventEmitter()
+
+      var injector = new di.Injector([{
+        config: ['value', {basePath: '/base/path', urlRoot: '/', httpModule: http2, protocol: 'https:', httpsServerOptions: credentials}],
+        customFileHandlers: ['value', customFileHandlers],
+        emitter: ['value', emitter],
+        fileList: ['value', {files: {served: [], included: []}}],
+        capturedBrowsers: ['value', null],
+        reporter: ['value', null],
+        executor: ['value', null],
+        proxies: ['value', null]
+      }])
+
+      server = injector.invoke(m.createWebServer)
+    })
+
+    it('should be an instance of httpModule provided in config', () => {
+      expect(server instanceof http2.Server).to.equal(true)
+    })
+  })
 })