Updated the files.

my-app/node_modules/karma/lib/events.js

@@ -0,0 +1,67 @@
+'use strict'
+
+const EventEmitter = require('events').EventEmitter
+const helper = require('./helper')
+
+function bufferEvents (emitter, eventsToBuffer) {
+  const listeners = []
+  const eventsToReply = []
+
+  function genericListener () {
+    eventsToReply.push(Array.from(arguments))
+  }
+
+  eventsToBuffer.forEach((eventName) => {
+    const listener = genericListener.bind(null, eventName)
+    listeners.push(listener)
+    emitter.on(eventName, listener)
+  })
+
+  return function () {
+    listeners.forEach((listener, i) => {
+      emitter.removeListener(eventsToBuffer[i], listener)
+    })
+
+    eventsToReply.forEach((args) => {
+      EventEmitter.prototype.emit.apply(emitter, args)
+    })
+
+    listeners.length = 0
+    eventsToReply.length = 0
+  }
+}
+
+class KarmaEventEmitter extends EventEmitter {
+  bind (object) {
+    for (const method in object) {
+      if (method.startsWith('on') && helper.isFunction(object[method])) {
+        this.on(helper.camelToSnake(method.slice(2)), function () {
+          // We do not use an arrow function here, to supply the caller as this.
+          object[method].apply(object, Array.from(arguments).concat(this))
+        })
+      }
+    }
+  }
+
+  emitAsync (name) {
+    // TODO(vojta): allow passing args
+    // TODO(vojta): ignore/throw if listener call done() multiple times
+    let pending = this.listeners(name).length
+    const deferred = helper.defer()
+
+    this.emit(name, () => {
+      if (!--pending) {
+        deferred.resolve()
+      }
+    })
+
+    if (!pending) {
+      deferred.resolve()
+    }
+
+    return deferred.promise
+  }
+}
+
+exports.EventEmitter = KarmaEventEmitter
+exports.bufferEvents = bufferEvents