wait until all events has been sent to the main process - refs webdri…

…verio/webdriverio#1713

lib/adapter.js

@@ -47,6 +47,9 @@ class MochaAdapter {
             mochaOpts: {}
         }, config)
         this.runner = {}
+
+        this.sentMessages = 0 // number of messages sent to the parent
+        this.receivedMessages = 0 // number of messages received by the parent
     }
 
     options (options, context) {
@@ -104,6 +107,8 @@ class MochaAdapter {
             this.runner.suite.afterAll(this.wrapHook('afterSuite'))
         })
         await executeHooksWithArgs(this.config.after, [result, this.capabilities, this.specs])
+        await this.waitUntilSettled()
+
         return result
     }
 
@@ -219,7 +224,8 @@ class MochaAdapter {
             this.sendInternal(event, message)
         }
 
-        this.send(message)
+        this.sentMessages++
+        this.send(message, null, {}, () => ++this.receivedMessages)
     }
 
     sendInternal (event, message) {
@@ -233,6 +239,19 @@ class MochaAdapter {
         return process.send.apply(process, args)
     }
 
+    /**
+     * wait until all messages were sent to parent
+     */
+    waitUntilSettled () {
+        return new Promise((resolve) => {
+            const interval = setInterval(() => {
+                if (this.sentMessages !== this.receivedMessages) return
+                clearInterval(interval)
+                resolve()
+            }, 100)
+        })
+    }
+
     load (name, context) {
         try {
             module.context = context

test/adapter.spec.js

@@ -162,6 +162,25 @@ describe('mocha adapter', () => {
             })
         })
 
+        it('should wait until all events were sent', () => {
+            const start = (new Date()).getTime()
+            let promise = adapter.run().then((failures) => {
+                const end = (new Date()).getTime();
+                (end - start).should.be.greaterThan(500)
+                failures.should.be.exactly(1234)
+            })
+            adapter.emit('foobar', {}, {})
+            adapter.emit('foobar2', {}, {})
+            process.nextTick(() => run.callArgWith(0, 1234))
+
+            setTimeout(() => {
+                send.args[0][3]()
+                send.args[1][3]()
+            }, 500)
+
+            return promise
+        })
+
         after(() => {
             Object.defineProperty(process, 'cwd', {
                 value: originalCWD