fix(report): waiting promise resolve in onExist method fix karma-runn…

…er#418

onComplete are async method which should bw complete in onExit method

lib/reporter.js

@@ -218,11 +218,13 @@ var CoverageReporter = function (rootConfig, helper, logger, emitter) {
     coverageMap.merge(result.coverage)
   }
 
+  const promiseCollection = []
+
   this.onRunComplete = async function (browsers, results) {
     const checkedCoverage = {}
 
     for (const reporterConfig of reporters) {
-      await Promise.all(browsers.map(async (browser) => {
+      const promise = Promise.all(browsers.map(async (browser) => {
         const coverageMap = coverageMaps[browser.id]
         if (!coverageMap) {
           return
@@ -266,10 +268,13 @@ var CoverageReporter = function (rootConfig, helper, logger, emitter) {
           report.execute(context)
         })
       }))
+      promiseCollection.push(promise)
+      await promise
     }
   }
 
-  this.onExit = function (done) {
+  this.onExit = async function (done) {
+    await Promise.all(promiseCollection)
     if (typeof config._onExit === 'function') {
       config._onExit(done)
     } else {

test/reporter.spec.js

@@ -141,9 +141,9 @@ describe('reporter', () => {
       mkdirIfNotExistsStub.resetHistory()
     })
 
-    it('has no pending file writings', () => {
+    it('has no pending file writings', async () => {
       const done = sinon.spy()
-      reporter.onExit(done)
+      await reporter.onExit(done)
       expect(done).to.have.been.called
     })
 
@@ -298,6 +298,20 @@ describe('reporter', () => {
       expect(mkdirIfNotExistsStub).not.to.have.been.called
     })
 
+    it('should calls done callback when onComplete event will be complete', async () => {
+      reporter = new m.CoverageReporter(rootConfig, mockHelper, mockLogger)
+      reporter.onRunStart()
+      browsers.forEach(b => reporter.onBrowserStart(b))
+      reporter.onRunComplete(browsers)
+      const done = sinon.stub()
+
+      const promiseExit = reporter.onExit(done)
+
+      expect(done.notCalled).to.be.true
+      await promiseExit
+      expect(done.calledOnce).to.be.true
+    })
+
     it('should create directory if reporting text* to file', async () => {
       const run = () => {
         reporter = new m.CoverageReporter(rootConfig, mockHelper, mockLogger)